Precise laser orientation aids will help you when you are hanging up paintings for example it comes with an angle scale ruler vertical and horizontal spirit level 2 scribers and 2 lasers batteries are supplied technical details accuracy of the spirit levels 05 mmm accuracy of the angle lasers 1 accuracy of the spirit level laser 05 laser wave length 650 nm laser output 1nw laser class 2 power supply 3 x lr44 2 x lr03 aaa