Ditto on what Hitthespot said...most waterproof lights are NOT submersible...checks the spec's...this usually has to do with the tolerances between the O-Ring and the body, and are usually given only for "informational purposes". For example, "Waterproof" to "MIL-STD-810F, Method 512.4" only means that it meets requirements for fording operations...if you have this light in your bag on the outside of a tank/hummer, crossing "rough" waters, it will stay dry on the inside for AT LEAST 30-Minutes, and still function. If it say's "water/weather proof", that means that the manufacturer "thinks" it is. Until a light has a MIL-Spec (military specifications) attached to it(meaning that it was actually subjected to those conditions), the "weather/water-proof" statement is only realible as the light/manufacturer it-self.