M3 stylus with 4.0 mm diameter x 10.0 mm long ruby cylinder, 2.0 mm carbide stem, and 4.0 mm diameter x 7.0 mm long stainless steel base. Overall stylus length is 40.0 mm. Stylus weight is 2.20 grams. 

Cylinder styli are used to probe narrow edges, such as those found on stampings and sheet metal. They are not suitable for high-accuracy work because the cylindrical form is less precise than a sphere. Please contact Q-Mark with any questions about calibrating or using cylinder styli.