The Twin Power Pack for the CooLED 50 Light allows usage of the light when there is no AC outlet available. The twin pack takes 24 “AA” batteries, either NiMH or alkaline. Recommended are 2500 mAh or higher NiMH as they are commonly available and inexpensive allowing for up to 1000 charges and producing 45 minutes of full power light. This battery pack attaches to the top of the light using the two shoes that come with the light and then plugs into the receptacle on the back of the light.