Self-levelling system. Laser for horizontal, vertical and diagonal line projection. Plumb function for transferring a point from floor to ceiling. Can project a perfectly right-angled cross onto the wall. Great for tile laying, picture hanging, etc. Working range: Up to 10 m. Laser class II. 635 nm. Accuracy: ±0.5 mm/m. 4 x AA/LR6 batteries, storage case and wall mount included.