1,Long working life 2,Anti-rust and waterproof 3,Low price and good quality 4,The materials are bearing steel Our ... ,Spherical Roller Bearings, Tapered Roller Bearings, Automotive Bearings, Thrust Ball Bearings, and also dealing in household appliances ,auto parts, motor parts etc ... /closure: open bearing, Z, ZZ, RS, 2RS,RZ, OPEN4) Vibration and Noise level: Z1, Z2.5) Precition level: ABEC-1..6 ...