This item will be shipped within One Week Returns Subject to 15% restocking Fee RCSM-20mmL Rubber Cartridge Narrow Inner Ring Ball Bearing Eccentric Locking Collar 20mm Inner Diameter RCSM-20mmL Rubber Cartridge Narrow Inner Ring Ball Bearing, bearing is cylindrical Cartridge interliner made of conductive rubber, it uses to dissipate static, it reduces noise and vibration, bearing is use in many fan, blower and other HVAC applications, bearing is narrow inner ring, Standard seal is RST tight riding, full cover, and metal shroud seals.