A body implanted device including a container having an opening through which extends an electrical feedthrough. The feedthrough includes a terminal of bio-stable material. A glass insulator is positioned around the terminal. The glass insulator is chosen from a CABAL-12 type composition or variation thereof. The terminal is comprised of a material which has thermal expansion characteristics compatible with the glass seal. For glass seals having a thermal expansion in the range of 6.8 to 8.0.times.10.sup.-6 in/in/.degree. C. the terminal is comprised of a thin layer of titanium metallurgically clad over niobium or tantalum. For glass seals having a thermal expansion in the range of 8.0 to 9.0.times.10.sup.-6 in/in/.degree. C. the terminal is comprised of platinum, platinum-iridium or alloys of either, or of pure titanium.