Model: MR52-ZZ Color: Silver Material: Metal Size: 2 x 5 x 2.5mm (Inner Diameter x Outer Diameter x Thickness) Bearings reduce friction by providing smooth metal balls or rollers and a smooth inner and outer metal surface for the balls to roll on. The balls or rollers "carry" the load, allowing the device to rotate smoothly. Package Contents: 100pcs x Bearings 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.