The DEWALT DW085K 5 Beam Laser Pointer is accurate to 1/4″ at 100′. The single lever power switch locks the pendulum in the off position for added durability. It has a micro adjust knob for precise alignment of 90Degree intersecting lines over greater distances and a built-in magnetic pivoting bracket mounts easily on metal surfaces. An integrated track clearance enables users for fast and easy bottom and top track installation. Also, an overmolded housing helps maintain calibration under jobsite conditions. The focused laser beam keeps dot size small over longer distances for improved accuarcy and visibility. Uses (4) AA Batteries, included.