Unthreaded stylus holder with M5 threaded base. Holds up to 5 unthreaded styli with 1.0 mm diameter stems. Features a 1.5 mm diameter knock-out hole through threaded base. Stainless steel, with stainless steel set screws. Weight is 7.38 grams. Includes one 0.7 mm hex wrench (shown). Compare to Renishaw A-5555-0105 and Zeiss 600341-8367-000.