... . low friction coefficient2. Able to move in both radial and axial directions3. High precision, working in high speed4. Different specs ,also ... colour,POMS,POMBS,POMM,POMBM,POMT,POMBT type;NO 2:Aluminum bushing(white,cupreous colour,ALBS,ALS,ALBM,ALM,ALBT,ALT ... (Joann).I'm glad to give you the best service. Aluminum/Brass/POM bearing cage