1.High Precision Deep Groove Ball Bearing 6004 2.High Speed 3.Material:Chrome/Carbon/Stainless steel 4. ... Details MaterialChrome steel, Carbon steel, stainless steel, Bearing SteelSized:20mm D:42mmB: 12mmCagesteel punching cage,brass cage,nylon cage Seals typeOPEN ... performance is very high. High Precision Deep Groove Ball Bearing 6004