Extech’s DT40M measures distance up to 40 m (131 ft). It can calculate area and volume and the integrated Pythagorean theorem allows the user to take indirect measurements. Other features include continuous measurement with min/max distance tracking, 20 point memory, addition/subtraction of sequential readings, front or rear edge reference, and a stakeout function. Large quad backlit LCD display and double molded housing. It also has a handy built-in bubble level and comes with a wrist strap and batteries.