Compared to standard series cast iron units, bearing units in the new stainless series provide superior resistance to corrosion and longer lubrication life in a clean unit with low torque characteristics. The solid grease lubricating the bearing has been heat hardened and is a mixture of lubricant and ultra high molecular weight polyethylene. The solid grease reduces leakage, prolonging lubricant life especially when used under conditions of vibration or centrifugal force. The maximum operating temperature of bearings with solid grease generally falls between -20°C ai +80 °C, however it must be less than 60°C for continuous operation.