Professional High Precision Tool! Depth Measuring Base allows the conversion of a standard caliper to a depth gauge. It attaches to the bottom end of calipers to aid depth measurement. Its locking nut secures the base to the caliper. Features: Made of Stainless Steel, high precision ground and hardened Easily attached with screw knob. No modification to caliper. Allow using a standard caliper as a depth gauge Accommodates blades up to 5/8" or 16mm wide Total span 2.93" Fit Starrett, Mitutoyo, and Brown & Sharpe 6" and 8" calipers Caliper in photo is not included