deep groove ball bearing--6003 Pack of 10 Ball Bearings 6003-2RS for the 17mm bore bearings, 6003-2RS inner diameter is 17mm, 6003-2RS Bearings are made of Chrome Steel, 6003-2RS can rotate up to 15000 rpm, each 6003-2RS bearing has 2 Rubber Seals to protect the bearing from dust or any possible contamination, 6003-2RS bearings are pre-lubricated with grease, Bearings 6003-2RS are packed 10 bearings in one plastic tube.