Combined with the rechargeable upgrade kit, the 20-watt C8 becomes the light of choice for most diving situations. In remote locations where electricity is unavailable the C8 will run 4-4.5 hours on a set of batteries using the 13-watt lamp. The long shelf life of alkalines will insure the light is ready when you need it in an emergency. Back home or where there is electricity, power the C8 up to its 20 watt maximum by adding the accessory Rechargeable Upgrade Kit. The unique dual lamp system allows you to switch between two different lamps underwater. Switch to a second lamp if the first burns out. When using the Rechargeable Kit switch between high-beam (20 watt) and low beam (13 watt). Use the high beam for spotting distant objects and the low beam for extending battery life.