1,Electronic self-leveling, 2,wide leveling range, 3,high precision and stability Specifications:Laser wavelength: 635 nmLaser ... IIAccuracy: ±1/4"/100 ft. (±1 mm/5m)Self-leveling range: ±3°Power: 3x AA alkaline batterySize: 10" x23 5/16 ... connected with the tripod by 5/8' thread Automatic 500m Range Rotary Laser Level Self-Leveling