Style DRU-BHT rod seals are molded in Freudenberg� AU 30000 urethane. These seals are specifically designed to seal on their inside diameter and engineered to attain maximum life and reliability in dynamic rod sealing. This high tear-resistant urethane demonstrates stability throughout a wide range of temperatures. In addition, this material is well suited to mineral and biodegradable hydraulic fluids as well as being resistant to hydrolysis.