M2 stylus with 4.0 mm diameter ruby ball, 2.0 mm diameter carbide shaft, and 3.0 mm diameter x 6.0 mm long stainless steel base. Stylus length to ball center is 10.0 mm. Stylus weight is 0.49 gram.  Compare to Renishaw A-5555-0312 and Zeiss 602030-8015-000.