General Tools 729 4 in slide caliper delivers quick and accurate inside and outside diameter measurements. This slide caliper provides inside and outside readings in both etched and filled 16ths and 32nds graduations. A decimal equivalents chart on the caliper’s back side is helpful in making measurement calculations. The durable polished stainless steel construction is coupled with a compact design makes this caliper a great addition to any workbench or toolbox.