Ball Bearing 5/8" x 1 3/8" x 7/16" Ceramic Hybrid 1623-2RS Chrome Steel and Ceramic Balls Hybrid ceramic chrome steel sealed bearings 1623-2RS Bearings with ZrO2 Ceramic Balls, Bearings 1623-2RS is a popular size that could be used in many application that uses this size 5/8" x 1 3/8" x 7/16", each 1623 bearings is closed with 2 Rubber Seals, double sealed, one seal from each side, to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with Oil.