M3 stylus with 0.5 mm diameter ruby ball, tapered carbide stem, and 4.0 mm diameter x 6.0 mm long stainless steel base. Minor stem diameter is 0.3 mm, major diameter is 1.0 mm. Overall stylus length is 18.0 mm. Stylus weight is 0.58 gram. Compare to Zeiss 626123-5444-018.