The main function of the Rod Wiper is to keep the rod and cylinder clean and free from foreign matter; thus preventing premature failure. The Rod Wiper is not a pressure sealing element, yet it prevents possible abrasive effects which may result if contaminants were to reach the sealing and rod bearing elements.   The standard materials for universal polyurethane wiper (U, D or ST) are high durometer urethane or hytrel®. They are also available in molythane, polymyte, fluoromyte, nitroxile, and viton. Consult sales for price and availability. Temperature: -65° to 200°Fre.