✔ Laser light has an on/off power switch. ✔ Class IIIA laser product.✔ This is a Class 3R laser product, Power output ＜ 1mW.Ø Note: Laser Ranging Error,that is given as "+/-2mm at 10m and 25m".Ø Note: If the laser is the Vertical Level or the Horizontal Level, you shouldn't adjust the Beam.