Intrinsically safe and MSHA approved (Mining, Safety & Health Administration) - explosion proof containment not required, Used in above ground and underground operations - extremely rugged with 6mm optics for a small dot at a distance, Laser beam is aligned to be concentric with the outside diameter of the brass housing, This allows the installer to use the outside of the case for centering and positioning the beam, Precision beam alignment - self-cleaning threads - no tools required, Milled Flat on bottom - use as an installation laser level, Large 12mm optics - 20 times brighter than standard lasers, "O" ring seal - water and oil proof to IP67 standards and solid brass - proven to work in hard environments, 40-6264 Includes > Laser, adjustable spad hanging tabs, 2 "AAA" alkaline batteries and an instruction manual