Used as electric door top wheel, pan door nylon clamping wheel, iron door wheel, electric door guide wheel, track wheel and pulley With two 6201 Insert Bearings Great replacements for the old or damaged one size: 48x50mm Material:nylon color:yellow Package Contents: 6 x Guide Wheels Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.