M3 stylus with 1.0 mm diameter ruby ball, stepped carbide stem, and 4.0 mm diameter x 6.0 mm long stainless steel base. Minor stem diameter is 0.8 mm; major stem diameter is 1.0 mm. Overall length is 16.0 mm. Stylus weight is 0.65 gram. Compare to Zeiss 626123-0044-016.