The sealed multiconductor feedthroughs can be supplied in a variety of metals including aluminum and stainless steel. The feedthrough chambers can be Teflon coated to assure trouble-free operation in the most corrosive environments. A variety of "O" rings in various materials such as buna-N, Viton, silicone rubber and Teflon allow operation over a wide range of temperatures and conditions. An internal screw-in pressure ring provides constant pressure to the "O" ring seal and holds the connection header in place. This permits mounting of the feedthrough in any position to allow full service of the terminations without disturbing the chamber environmental condition. The hermetic seals between the environment side and the ambient side maintain the integrity of the operating environment.