Spectra Precision GL412N Grade Laser. Easy-to-use menu-driven interface reduces learning time and eliminates complex button pressing to activate advance features. The exact grade can be entered in single axis and is self-leveling. One person elevation control with 2,600 ft (800 m) diameter range increases productivity.RC402N radio remote control allows control of all laser functions from up to 330 ft (100 m) away. Durable design reduces downtime due to drops and tripod tip-overs. Automatic Grade Match eliminates time-consuming and error-prone calculation.