The CST/Berger 57-ALHVGD green beam self leveling horizontal and vertical interior and exterior rotary laser level with LD440G detector series Delivers, accurate. reliable, performance for the professional who demands fast and accurate leveling. The CST/Berger 57-ALHVGD is dual-slope capable in both horizontal and vertical position with cross-axis leveling make the ALHV-G suitable for indoor and outdoor jobs.