Features:   Two or three 635nm, class II laser diodes. Levelling accuracy: 5/32" at 30' (4mm at 9m) Horizontal & vertical line accuracy (end to end): ±3/32" at 10' (±2mm at 3m). Ideal for finish carpentary, floor and wall tile installation, wallpaper applications. Self-levelling ensures accurate results. Out-of-leveling-range sensor/automatically shut off. Use three "AA" cell batteries provide ±15 hours of use.