SCI501 dive light is minimized the absorption and lumen loosing from optical lens as well as the reflector itself; it creates real 1000 lumen output. The waterproof is rated to 650ft/200m and more for technical divers. The size is smaller comparing the sizes we are used to design for 8 degree beam angle; but this won’t compromise the distance of beam. The hard anodized aluminum alloy is making this light no damage to the surface.