A unique and revolutionary design features an interchangeable power supply. The Responder can be powered by either a 4.8-volt Ni-Cad rechargeable battery pack or four C-cell Alkaline batteries - a must-have power option for professionals on the job. With the rechargeable pack, the Responder Division 1 provides more than 2 hours of continuous light and a quick charge time of 2 hours. Get called to another emergency before you have time to recharge? Simply unscrew the battery cover, remove the rechargeable pack and replace it with four C-cell Alkaline batteries and you immediately have five more hours of light output!