HIGH QUALITY: These bearings are made of high quality carbon steel, very durable and have a long service life. DOUBLE SHIELDED DESIGN: They are double shielded to prevent the ingress of contaminants and save lubricant, well protected. V-GROOVE: The bearings have 1.5mm deep V-grooves that usually run on a rail or track, performing well. WIDE APPLICATION: These are special bearings used in many linear motion systems. WIDE APPLICATION: These are special bearings used in many linear motion systems. ball bearing v-groove bearing deep groove 6mm pulley v-groove bearing v bearing miniature steel ball bearing rail linear motion rail small ball bearing wheel mini ball bearing Specification: Material: Carbon steel Model: V624ZZ Inner diameter: 4mm / 0.15 Outer diameter: 13mm / 0.51 Thickness: 6mm / 0.23 V-groove width: 5mm / 0.19 V-groove depth: 1.5mm / 0.06 Quantity: 10pcs Package includes: 10 Bearings