Spectra Precision Laser LL500 Exterior Self-Leveling Laser Level With HL700 Receiver Includes HR500 Receiver with rod clamp Accuracy + or - 1/16" @ 100' Operating diameter 1,600' Includes 4 D-cell alkaline batteries, 80 hours Warranty 2 Years Class 2 Laser and &lt;3mW (less than 3 Milliwatts)