If you are purchasing (or already own) a Supernova, these are the replacement batteries. The Supernova is powered by a CR2032 Lithium battery pack. After approximately 250 hours of use, the batteries in the Supernova will start to wear out. Make sure you order the replacement batteries here - because most stores will charge 4 to 5 times more than what we charge for these little guys. This is a strip of 4 battery packs which will make sure your Supernova never runs out of juice.