6904-2RS Ceramic Hybrid C3 Ball Bearing Chrome Steel and Ceramic Balls 20 x 37 x 9 mm 6904-2RS Hybrid ceramic chrome steel sealed bearing with ZrO2 Ceramic Balls Electric motor quality, 6904-2RS is a popular size that could be used in many applications that uses this size 20mm x 37mm x 9mm, each 6904-2rs bearing is closed with 2 Rubber Seals, double sealed andone seal from each side to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease, Bearing has industrial packaging.