The Standard Gage 00564001 T-Bar Depth Measuring Base attaches to the ruled blade of 6" (150mm) scale calipers to aid depth measurement and is 76.2mm long to span wide holes and recesses for stable measurements. It has a locking nut for securing in place along the blade and accommodates blades up to 16.2mm wide.

Depth gauges are precision measuring instruments used to determine the depth of any shape that has a step, groove, or slot. These gauges often take the form of sliders that travel on a measuring beam or rods, are moved to position by hand, and then adjusted with a calibrated screw. The base of the gauge rests at the top of the shape whose recession is to be measured, while the beam or rods extend to the bottom of the recession to determine the measurement. Gauge position is read from a graduated scale, dial, counters, or an electronic display.

Standard Gage manufactures precision measuring equipment and metrology hand tools. The company is headquartered in North Kingstown, RI.