The SL3 eLED (L2) is a popular back-up or secondary light for advanced dives at night. It's also fantastic for wreck diving and cave diving expeditions. It's also a great light for peeking under ledges and into cracks in daytime dives.
Its compact size makes the light ideal for bringing along on vacation, and because it uses widely available disposable C-cell batteries, it will always work even where electricity is not always available, and not have to worry about charging.