The MSE® seal consists of a PTFE or other polymer energized by a corrosion-resistant metal spring. When the seal is seated in the gland, the spring is under compression and applying force on the gland-sealing surfaces. This creates a tight barrier to prevent gas or fluids from leaking. The spring also provides resiliency to compensate for seal wear, gland misalignment or eccentricity. While spring force provides adequate force for sealing at low pressure, at high pressure the system pressure augments the spring force to provide an even tighter seal. MSE seals are precision machined from PTFE, filled PTFE and other high-performance polymers. MSE seals work consistently under a wide array of temperatures and pressures. Greene, Tweed offers over 100 jacket materials, four standard spring materials, and four standard spring designs to meet your sealing needs.