Self-levelling int/ext rotary laser kit provides horizontal self-levelling for quick and easy set-up. Protected rotary head and weatherproof design deliver interior and exterior job-site durability. Horizontal self-levelling for quick and easy set-up. Enclosed levelling vial, manual levelling in vertical mode, for job-site durability. Protected rotary head and weatherproof design deliver interior and exterior job-site durability. Digital laser detector extends interior and exterior range to 600 ft. Standby mode allows the user to pause the laser while transitioning from horizontal to vertical.