... steel, stainless steel, pvc, nylon2. zinc-plating, galvanizing, chromeorplated3. Use press bearing or precision bearing4. shaft could be spring-loaded ... mounting. Or in fixed shaft type.4. GCS non-drive gravity roller could be made of nylon, weld pipe, ... , pvc roller, sprocket roller, retractable roller, taper roller, drive roller, non-drive roller. All these roller used in bulk material handling ...