DL premium pistons are fully interchangeable with other API standard designed pistons and deliver maximum performance in almost all drilling conditions. The hub is formed from high grade steel. The piston rubber is made from specially formulated compounds which are resistant to the effects of heat,oil and water. The multi-ply fabric reinforced backings used in the production of the piston rubbers provide positive,wear resistant seals. High tensile strength, resistance to chemicals, hydrocarbic.