The piston seal type Aston Seals KPR is composed of a dynamic seal element which assures exceptional high sealing performance. Two compact and small seal edges ensure perfect fluid control and concentrate the load against the dynamic surface. The cavity between the two external seal edges keeps a small quantity of fluid which reduces friction and wear. Side grooves ensure that pressure loads the energizing element in all work conditions. - A nitril rubber element with low permanent deformation as energizing component on the static side. The hardness and the rectangular cross-section prevent twisting of the static element in the groove.