Self-calibrating, compact, designed for operation indoors up to 30 m and outdoors up to 50 m with a detector. 1 horizontal and 2 vertical lines which merge into a 90 angle. Angle and height adjustable feet. Accuracy: 0.2 mm/m. The set includes a thread adapter: 5/8"" (16 mm) to 1/4"" (6 mm)