Extech’s DT40M measures distance up to 131ft (40m). 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.