M3 stylus with 0.5 mm diameter silicon nitride ball, stepped carbide stem, and 4.0 mm diameter x 5.0 mm long stainless steel base. Minor stem diameter is 0.3 mm, intermediate diameter is 0.6 mm, and major diameter is 0.3 mm. Overall stylus length is 20.0 mm. Stylus weight is 0.65 gram.