20pcs 624ZZ 4mm V Groove Sealed Guide Pulley Rail Ball Bearing 4x13x6mm<div style="text-align: left;"><strong>[Product Information]</strong><br><ul><li>Wire pulley groove，Wide application</li><li>This item is ordinary precision， adaptation to low speed， low load applications</li><li>Material:High carbon steel</li><li>Dimension:(Inside diameter)4mm x (outer diameter)13mm x (thickness)6mm</li><li>V groove width: 4mm.V groove deepness: 1mm</li></ul></div><img src="http://ecx.images-amazon.com/images/I/41R2vsa0sQL.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/31Gu54XPcaL.jpg" noproxy>