Bring a spare pack along with you and make sure you've got back-up power when and where you need it most! Holds 4 AA Batteries Warning [https://productimageserver.com/prop65/6pt.png]WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov [http://P65Warnings.ca.gov].