The Hallite 653 is a buffer seal developed to work in conjunction with high performance rod seals, such as the Hallite 605 and 621. It is also interchangeable with common PTFE buffer seal housings.The seal, which is manufactured in Hythane 181, is designed to provide a valve action to prevent excessive pressure build up in the cavity between the buffer seal and the rod seal. A polyacetal anti-extrusion ring is fitted to provide maximum extrusion resistance against shock pressure loads.The Hallite 653 is a patented product:European patent no. 0427554BI.U.S.A. patent no. 5088747.