LEDX was first to have a back-up battery, the small battery that could save the race or to use on your run if something happened with the regular battery. Now we are launching LEDX Backup Light, a completely separate light that has its own power supply. Snaps on the lamp before starting. Can be switched on in a second, giving a light of about 350 lumen and weighs only 20 grams, 60 grams with battery. LEDX Backup Light operates completely independently of the regular lamp and can also be used separately. Fits Cobra 5500, Mamba 3000, and Kaa 1250 when mounted on the Headgear Pro.