Underwater Kinetics C4 eLED (L2) w/ NiMH Battery/Charger Safety Yellow Gear Bags - Backpacks Mares has addressed this

Mares has addressed this

S HOOD AIR VENTING SYSTEM with two valves

and kept water tight

Lenses are carefully crafted to provide optical clarity and the crystal silicone skirt assures a precise comfortable fit

Underwater Kinetics C4 eLED (L2) w/ NiMH Battery/Charger Safety Yellow Gear Bags - Backpacks Mares has addressed thisThe classic C4 primary dive light has received a major upgrade in this L2 model, increasing the lumen output up to 1000 lumens. The light uses airline safe Nickel metal hydride batteries, which can be shipped in your luggage, unlike lithium batteries, which must be kept in the cabin during travel. This makes the rechargeable C4 perfect for traveling.