General description Bearings are made of high-quality steel for durability and long life. These mini ball bearings are double shielded to prevent contaminant ingress and save lubricant. They feature a 1.8mm deep U-groove that typically rolls on a rail or track, making them perfect for various linear motion systems. Technical specifications Model: U624ZZ Inner Diameter: 4mm / 0.15 inch Outer Diameter: 13mm / 0.51 inch Height: 7mm / 0.27 inch U-Groove Width: 5.2mm / 0.2 inch U-Groove Depth: 1.8mm / 0.07 inch Color: Silver Material: Steel Size: 13 x 7 x 4 mm Package Contents: 100 x Bearings Other information Note: Light reflection and different displays may cause the color of the item to differ slightly from the real thing. The measurement allowed error is +/- 1-3 cm.