Body implanted device with electrical feedthrough

A body implanted device comprising:

• a container having an opening between the exterior and interior of said container;
• an electrical terminal extending from the interior of said container through the opening in said container to the exterior of said container, said electrical terminal selected from the group consisting of platinum, platinum-iridium alloys, titanium or titanium clad over niobium or tantalum to a thickness in the range of 50 to 300 microinches;
• and
• a glass insulator positioned around a portion of said terminal in sealing engagement with said terminal and said container, said glass insulator having a chemical composition consisting essentially of about 20 mole % Al.sub.2 O.sub.3, about 20 mole % CaO, between about 1 mole % and 15 mole % SiO.sub.2, between about 25 mole % and 40 mole % B.sub.2 O.sub.3, between about 0 mole % and 20 mole % MgO, between about 0 mole % and 20 mole % BaO and between about 0 mole % and 10 mole % SrO.