All PerkinElmer pumps contain a high and low pressure piston seal. In addition to the standard high pressure seal, we provide extended performance seals for more specialized requirements. The chemically resistant seal is composed of a graphite PTFE material. This seal is inert to an extended range of solvents, such as buffers. It cannot be used with high flows or pressures in excess of 3000 psi. Whenever replacing the low pressure seal, the Low Pressure Seal Back-Up Ring should also be replaced.