The Self-Leveling Interior/Exterior Rotary Laser Level from DEWALT is accurate to 1/4 in. at 100 ft. and constructed to withstand the abuse of rugged job site conditions. The unit is self-leveling in horizontal mode, and the addition of arrow buttons used for manual leveling in vertical mode are far more intuitive than traditional knobs. Sharp and bright, the beam can be seen up to 100 ft. indoors and can be recognized up to 1200 ft. diameter outdoors with the included detector. The laser also offers a weather-resistant housing for durable and accurate performance