【異形工字釘】_異形工字釘價(jià)格_異形工字釘批發(fā)_異形工字釘廠家

共找到 6 個(gè)相關(guān)產(chǎn)品馬可波羅 > 針、釘> 異形工字釘

類目：

針、釘 (6)

品質(zhì)商家熱力排行

全國(guó)

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="49" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100399473358.html">供應(yīng)彩色工字釘 8*23mm透明工字釘 異形工字釘 塑料工字釘
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100399473358.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>恒陽(yáng)/小號(hào)</div></td>
<td class="td_1"><div>包裝方式：</div></td>
<td class="td_2"><div>散裝</div></td>


</tr>
<tr>
<td class="td_1"><div>顏色：</div></td>
<td class="td_2"><div>彩色</div></td>
<td class="td_1"><div>規(guī)格：</div></td>
<td class="td_2"><div>直徑8mm</div></td>


</tr>
<tr>
<td class="td_1"><div>型號(hào)：</div></td>
<td class="td_2"><div>小號(hào)</div></td>
<td class="td_1"><div>材質(zhì)：</div></td>
<td class="td_2"><div>鋼絲</div></td>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
[浙江金華] <a  data-num="3"  data-flag="0" target="_blank">
浙江武義恒陽(yáng)工貿(mào)有限公司
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
其他鎖具,拉手、把手,其他案頭用品,針、釘
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://yunmopin.cn.makepolo.com/contact_us.html?proid=100399473358">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):<strong>0.01</strong>元</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100399473358.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100399473358.html" target="_blank" data-num="7" data-flag="0" title="供應(yīng)彩色工字釘 8*23mm透明工字釘 異形工字釘 塑料工字釘"><img src="http://img2.makepolo.cn/images/formals/img/product/336/131/0d083b1b8da77fb4b1c4b5a5e64e91ae.jpg~tplv-1fgsepqywg-mp:280:210.image" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="供應(yīng)彩色工字釘 8*23mm透明工字釘 異形工字釘 塑料工字釘"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="47" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100389942498.html">供應(yīng)新型工字釘、異形回形針
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100389942498.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>七星/1205</div></td>
<td class="td_1"><div>顏色：</div></td>
<td class="td_2"><div>自選</div></td>


</tr>
<tr>
<td class="td_1"><div>包裝方式：</div></td>
<td class="td_2"><div>散6</div></td>
<td class="td_1"><div>型號(hào)：</div></td>
<td class="td_2"><div>1205</div></td>


</tr>
<tr>
<td class="td_1"><div>規(guī)格：</div></td>
<td class="td_2"><div>32*13mm</div></td>
<td class="td_1"><div>品牌：</div></td>
<td class="td_2"><div>七星</div></td>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
<a  data-num="3"  data-flag="0" target="_blank">
寧海縣七星文具廠
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
夾子,印章,名片架/座,其他案頭用品,塑料、樹
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://qq3426638.cn.makepolo.com/contact_us.html?proid=100389942498">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):面議</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100389942498.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100389942498.html" target="_blank" data-num="7" data-flag="0" title="供應(yīng)新型工字釘、異形回形針"><img src="http://img7.makepolo.cn/images/formals/img/product/582/720/2_489629e0dd880cfbb59c43a444669843.jpg~tplv-1exjxyof9i-1:280:210.image" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="供應(yīng)新型工字釘、異形回形針"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="41" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100367292440.html">供應(yīng)珠針，彩色異形包塑,鍍鎳回形針，彩色工字釘（大，中，�。�
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100367292440.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>MMY/回形針,工字釘</div></td>
<td class="td_1"><div>顏色：</div></td>
<td class="td_2"><div>彩色</div></td>


</tr>
<tr>
<td class="td_1"><div>包裝方式：</div></td>
<td class="td_2"><div>散裝</div></td>
<td class="td_1"><div>型號(hào)：</div></td>
<td class="td_2"><div>回形針,工字釘</div></td>


</tr>
<tr>
<td class="td_1"><div>規(guī)格：</div></td>
<td class="td_2"><div>多樣</div></td>
<td class="td_1"><div>品牌：</div></td>
<td class="td_2"><div>MMY</div></td>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
<a  data-num="3"  data-flag="0" target="_blank">
深圳市寶安區(qū)沙井美藝文具制品廠
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
文具套裝,其他文具及配件,直尺、三角尺、量
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://meimeiyi.cn.makepolo.com/contact_us.html?proid=100367292440">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):<strong>0.03</strong>元</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100367292440.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100367292440.html" target="_blank" data-num="7" data-flag="0" title="供應(yīng)珠針，彩色異形包塑,鍍鎳回形針，彩色工字釘（大，中，小）"><img src="http://img2.makepolo.cn/images/formals/img/product/576/634/d1483d121c40b19be0947a9f78ebb564.jpg~tplv-1fgsepqywg-mp:280:210.image" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="供應(yīng)珠針，彩色異形包塑,鍍鎳回形針，彩色工字釘（大，中，�。�"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="35" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100454738020.html">武義恒陽(yáng)圖釘平頭釘工字釘卡通圖釘異形圖釘金屬工字釘創(chuàng)意圖釘
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100454738020.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>恒陽(yáng)/3#</div></td>
<td class="td_1"><div>材質(zhì)：</div></td>
<td class="td_2"><div>金屬</div></td>


</tr>
<tr>
<td class="td_1"><div>品牌：</div></td>
<td class="td_2"><div>恒陽(yáng)</div></td>
<td class="td_1"><div>型號(hào)：</div></td>
<td class="td_2"><div>3#</div></td>


</tr>
<tr>
<td class="td_1"><div>顏色：</div></td>
<td class="td_2"><div>彩色</div></td>
<td class="td_1"><div>包裝方式：</div></td>
<td class="td_2"><div>散裝 按客戶要求</div></td>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
[浙江金華] <a  data-num="3"  data-flag="0" target="_blank">
武義艾尚葉工貿(mào)有限公司
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
智能鎖,垂釣用品套件,門鎖,酒類包裝,禮品盒
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://huixz.cn.makepolo.com/contact_us.html?proid=100454738020">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):<strong>0.01</strong>元</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100454738020.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100454738020.html" target="_blank" data-num="7" data-flag="0" title="武義恒陽(yáng)圖釘平頭釘工字釘卡通圖釘異形圖釘金屬工字釘創(chuàng)意圖釘"><img src="http://img7.makepolo.cn/images/formals/img/product/727/560/2_50f7e4c02689a924111ae046472cf353.jpg~tplv-1exjxyof9i-1:280:210.image" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="武義恒陽(yáng)圖釘平頭釘工字釘卡通圖釘異形圖釘金屬工字釘創(chuàng)意圖釘"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="8" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100367292453.html">供應(yīng)彩色異形回形針,鍍鎳回形針,工字釘,圖釘,鍍鎳大頭針,彩珠針
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100367292453.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>美藝/異形</div></td>
<td class="td_1"><div>品牌：</div></td>
<td class="td_2"><div>美藝</div></td>


</tr>
<tr>
<td class="td_1"><div>材質(zhì)：</div></td>
<td class="td_2"><div>金屬</div></td>
<td class="td_1"><div>包裝方式：</div></td>
<td class="td_2"><div>散裝</div></td>


</tr>
<tr>
<td class="td_1"><div>型號(hào)：</div></td>
<td class="td_2"><div>異形</div></td>
<td class="td_1"><div>規(guī)格：</div></td>
<td class="td_2"><div>多種</div></td>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
<a  data-num="3"  data-flag="0" target="_blank">
深圳市寶安區(qū)沙井美藝文具制品廠
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
文具套裝,其他文具及配件,直尺、三角尺、量
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://meimeiyi.cn.makepolo.com/contact_us.html?proid=100367292453">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):<strong>0.02</strong>元</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100367292453.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100367292453.html" target="_blank" data-num="7" data-flag="0" title="供應(yīng)彩色異形回形針,鍍鎳回形針,工字釘,圖釘,鍍鎳大頭針,彩珠針"><img src="http://img5.makepolo.cn/images/formals/img/product/715/21/1e2300158d22eabaf2efdff276c39171.jpg~tplv-izbs7asbod-1:280:210.image" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="供應(yīng)彩色異形回形針,鍍鎳回形針,工字釘,圖釘,鍍鎳大頭針,彩珠針"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

<div   id="rbrt3ahqxjx"   class="s_product_item">

<div   id="rbrt3ahqxjx"   class="s_product_content s_product_content_r">
<div   id="rbrt3ahqxjx"   class="s_product_title" score="4" pro_score="0">
<a target="_blank" class="plistk f14" data-num="1" data-flag="0" href="http://m.htjqly.com/product-detail/100454737975.html">工字釘異形工字釘塑料工字釘小號(hào)工字釘塑料掛釘
</a>

</div>
<div   id="rbrt3ahqxjx"   class="s_product_info">


<ul class="s_product_parameter">
<li id="rbrt3ahqxjx"    class="new_li">
<a href="http://m.htjqly.com/product-detail/100454737975.html" data-num="9"  data-flag="0" target="_blank">
<table class="new_list">

<tr>
<td class="td_1"><div>品牌/型號(hào)：</div></td>
<td class="td_2"><div>飛天/恒陽(yáng)/5#</div></td>

<td class="td_1"><div>所屬分類：</div></td><td class="td_2"><div></div></td>

</tr>
<tr>

<td class="td_1"><div>產(chǎn)品關(guān)鍵詞：</div></td><td class="td_2"><div>異形工字釘</div></td>
<td class="td_1"><div>最小采購(gòu)量：</div></td><td class="td_2"><div></div></td>

</tr>
<tr>


</tr>

</table>
</a>
</li>
</ul>


<div   id="rbrt3ahqxjx"   class="s_product_contact plistk">
[浙江金華] <a  data-num="3"  data-flag="0" target="_blank">
武義艾尚葉工貿(mào)有限公司
</a>

<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a  data-num="3"  data-flag="0" target="_blank">
智能鎖,垂釣用品套件,門鎖,酒類包裝,禮品盒
</a>
<span id="rbrt3ahqxjx"    class="s_product_line">|</span>
<a   data-num="4" data-flag="0" rel="nofollow" data-pstate="0" data-conurl="http://huixz.cn.makepolo.com/contact_us.html?proid=100454737975">
查看聯(lián)系方式
</a>
</div>
</div>
<ul class="s_product_param">

<li id="rbrt3ahqxjx"    class="plistk" id="">
報(bào)價(jià):<strong>1.00</strong>元</li>
<li id="fenlei"><a onclick="stat2_rf('36be0e3f215b480d98f15fce82e68fd3','pc_search_xp_1_show')" href="http://m.htjqly.com/product-detail/100454737975.html#inquiryPop" target="_blank" rel="nofollow">點(diǎn)此詢價(jià)</a></li>
</ul>
<div   id="rbrt3ahqxjx"   class="clear"></div>
<div   id="rbrt3ahqxjx"   class="value_add_service_con">
<ul>
</ul>
</div>
</div>
<div   id="rbrt3ahqxjx"   class="s_product_pic">
<div   id="rbrt3ahqxjx"   class="s_product_pic_box"><a href="http://m.htjqly.com/product-detail/100454737975.html" target="_blank" data-num="7" data-flag="0" title="工字釘異形工字釘塑料工字釘小號(hào)工字釘塑料掛釘"><img src="http://jic.makepolo.cn/img/none.jpg" onload="if(this.height>this.width*0.75){if(this.height>88){this.height=88;} }else{if(this.width>118){this.width=118;} }" alt="工字釘異形工字釘塑料工字釘小號(hào)工字釘塑料掛釘"  onerror="javascript:this.src='http://jic.makepolo.cn/caigou/new/images/none.jpg'" /></a></div>
</div>
</div>

熱門搜索:

產(chǎn)品圖片:

相關(guān)品牌:

本頁(yè)面馬可波羅為您提供 6條異形工字釘最新產(chǎn)品供應(yīng)商、制造商，囊括了異形工字釘產(chǎn)品的參數(shù)、型號(hào)、圖片、價(jià)格等信息，是異形工字釘產(chǎn)品的權(quán)威數(shù)據(jù)庫(kù)。我們會(huì)盡全力為您提供準(zhǔn)確、全面的信息!

馬可波羅網(wǎng)鄭重提醒：過低的價(jià)格和夸張的描述有可能是虛假信息，請(qǐng)買家謹(jǐn)慎對(duì)待，謹(jǐn)防欺詐。欺詐行為舉報(bào)郵箱：service@makepolo.com。了解更多防詐騙知識(shí)

泉州市一海三路科技有限公司福建省泉州市豐澤區(qū)丁榮路39號(hào)4樓416-3 閩ICP備18021442號(hào)-18

光山县| 吉首市| 朝阳市| 天门市| 宜川县| 吐鲁番市| 南开区| 肇庆市| 桦南县| 于田县| 大冶市| 通许县| 六安市| 连平县| 汉中市| 申扎县| 孟连| 正宁县| 合肥市| 浦东新区| 南平市| 华阴市| 易门县| 息烽县| 杭锦后旗| 常山县| 延长县| 思茅市| 澜沧| 信阳市| 丘北县| 德州市| 乐山市| 武鸣县| 敦化市| 申扎县| 高平市| 铜陵市| 普定县| 江川县| 扶风县|

国产精品一区二区久久精品,99精品久久精品一区二区,国产精品视频二区不卡,亚洲精品福利,亚洲欧美一区二区久久,一区二区不卡久久精品,国产日韩不卡免费精品视频

異形工字釘