The Nitrile Rubber piston was designed with a replaceable rubber Flex-Lip seal for high performance with water-based muds. The seal can be easily replaced in the field for a quick and economical drilling solution. Our proprietary blend of rubber and fabric used in the replaceable rubber piston resists the pinching and extrusion that commonly occurs in the heel of the piston. The use of synthetic fabric eliminates the loss of heel strength caused by water absorption, allowing the piston to achieve a higher level of performance compared to competing designs.