M3 XXT stylus for 1/4 star probe or L-shaped probe. 3.0 mm diameter silicon nitride ball with titanium base and 2.0 mm diameter Therm-X carbon fiber stem. A clamping screw or clamping stylus is placed through the 3.5 mm hole in the titanium base. Length is 30.0 mm. Weight is 0.74 grams.