M3 stylus with 2.0 mm diameter ruby ball, 1.4 mm diameter stainless steel stem, and 4.0 mm diameter x 12.0 mm long stainless steel base. Stylus length to ball center is 21.0 mm. Weight is 0.82 gram. Compare to Renishaw A-5000-3552, Mitutoyo K651147, Hexagon 03969302, and Carbide Probes 261-2R.