Just the number 4289 ,distinctive shape, in plan view, like a ship with a blunt end and a sharp end, 4.5x2x2mm, black body 3 in line gold plated legs .
3 of them used in a 1970s Bruel & Kjaer accelerometer.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
formatting link