The Hallite 51 is a heavy duty piston seal which, when installed in pairs, provides an excellent double acting piston design. It is particularly suitable for difficult operating conditions such as pressure surging, vibration or some misalignment.The seal is an assembly of three parts, a male adaptor, a V ring and a female adaptor. Both the V ring and female adaptor are made from rubberised fabric which has a durability and strength, it also retains lubricant at the sliding surfaces so friction and wear are kept to a minimum. The V ring being the primar seal is more flexible than the adaptor whic supports it and prevents extrusion damage. At higher pressures the adaptor deforms and becomes a secondary seal.The polyacetal male adaptor has grooves across the face to ensure pressure is evenly applied to the V ring.