How To Use A Self Leveling Laser To Set Your Grades For Beginners and Diy rs Accuracy fine 1.0mm (±1/32in), medium 2.0mm (±1/16in), coarse 5.0mm (±3/16in). geomax 6013520 zone20 h, self leveling rotary laser withzrb90 basic receiver. Battery life up to 100 hours. It has a self-leveling range of ±6 degrees and can be set to a manual slope mode for inclined applications.