Extech's DT40M can measure distances up to 40 meters (131 feet). It can calculate area and volume, and the inbuilt Pythagorean theorem enables users to make indirect measurements. Other features include continuous measurement with min/max distance tracking, 20-point memory, sequential reading addition/subtraction, front/rear edge reference, and a stakeout function. Large quad-backlit LCD display with double-molded casing. It also includes a built-in bubble level, a wrist strap, and batteries.