It’s a  9V Battery. This type battery generally use in DIY project like robotics, drone, toys. It has constant output voltage 9v and it is easy to use. Features  Constant 9V Output till lasts Metal Jacket Body Good Built Quality and hence Leakproof Easy to install and Replace Corrosion-free Connector Point for long-term use 0% Mercury and Cadmium. Environment-friendly OEM Compatible.