1. Material: carbon steel, chrome steel2. Closures: open, metal sealed, rubber sealed, nylon sealed3. Types: Z, ZZ, RS, RS, 2RS, RZ, 2RZ4. Bore size: 3-70mm, outside diameter: 6-125mm5. Application:sliding door/ window, furniture, motor, machinery, electric tools, sports apparatus, office equipment , scooter aluminum windows , shower blocks,..