6304-2RS Sealed Ball Bearings 20mm x 52mm x 15mm 6304-2RS Sealed Ball Bearings, the inner diameter is 20mm, 6304-2RS outer diameter is 52mm, 6304-2RS width is 15mm, 6304-2RS Bearings are made of Chrome Steel, each bearing 6304-2RS has 2 Rubber Seals to protect the bearing from dust or any possible contamination, also bearings are pre-lubricated with grease, 6304-2RS Bearings are packed 10 bearings in one plastic tube.