Bearing Type:6701ZZ / 6701-2RS(Different manufacturers, the bearing model (code) will be expressed differently.Such as 608Z=608ZZ=608-2Z=R2280ZZ=MR608Z=RV822, etc., all models of the title are the same bearing, please order according to the bearing size.) Bearing size:Inner diameter x outer diameter x width =12 x 18 x 4(mm) Abec1 The dimension accuracy is less than + 0.05mm and the speed is less than 500rpm, which is suitable for low speed and low requirement environment. Such as: low speed transmission equipment, castors, children's cars, toy cars and so on. ABEC3 The dimension accuracy is less than + 0.01mm, the handle is smooth, the rotation speed is less than 6000rpm, the noise is low, and the service life is long. It is suitable for motors, toy models, automobiles, electric tools, pneumatic tools, telecommunication equipment, fitness equipment, sports equipment and so on. ABEC5 The dimension accuracy is less than + 0.005mm, the handle is smooth, the speed is greater than 6000rpm, the noise is low, and the service life is long. It is suitable for high speed motors, high speed models, instruments, precision equipment, high grade toys and so on. Model Number: 6701 2RS Torque Capacity: 0 Surface Roughness: Ra 0.05 Coatings: 2RS Structure: Ball bearing Are standard parts: Standard part colour:Silver Material:steel size:12x18X4 mm Package Contents: 20 x 6701-2RS Bearing(with sealing ring) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.