Can use 4pcs AA batteries, voltage 1.2V-1.5V, can put two battery to use, the total output voltage between 2.5-3.7 (do not use rechargeable batteries recommended) and both sides of the battery box (such as the left two for a group, the right for a group) can not be mixed together to use.Do not install a rechargeable battery on one side and an unrechargeable battery on the other side, the output will be unstable.
 
 
Package List:1pcs battery case with cable