M5 stylus, 4.0 mm ruby ball, 2.0 mm diameter carbide stem, 11.0 mm diameter x 10.0 mm long stainless steel base. Stylus length to ball center is 20.0 mm. Stylus weight is 5.91 grams. Compare to Renishaw A-5003-5209 and Zeiss 626115-0400-022.