1.roller type: Carrying roller, return roller, impact roller, vertical roller, self-alignment roller, side roller, through roller, roller group etc. 2.roller inner structure and material:Shaft: bright drawn steel to required bearing tolerance Shaft end: both ends of tube are simultaneously machined and chamfered Bearing: single and double row deep groove ball bearing 2RZ and 2Z with C3 clearance Rubberheat vulcanization rubber. Wear resistant, anti-fire Seals: grease retaining inner seal with multi-stage labyrinth and retention cap with outboard rubbing flinger seal Lubrication: grease is lithium soap type grease with rust inhibitors Welding: mixed gas shielded arc welding end Our roller saves on repair and maintenance costs of the conveyor belt due to the concentric design which decreases vibration 3. Advantage: 1. High accurate steel pipes ensure the rollers with low vibration and noise.2. Multi-labyrinth seals achieve waterproof and dust proof.3. Adopt good bearing make sure the long lifetime, stable running and good quality. 4.The specification range that we can provide: Diameter: 50 to 219mm Length: 190 to 3,500mm Idler Dia mm 5063.57689102108114127133139.8152.4159165.2177.8190.7194219length190mm3500mm5. Meantime, we can produce according to the customers requirement.