The LiPo batteries are composed of a lithium-based cathode and anode separated by a polymer electrolyte they are used in, phones, cars, bikes, etc and all types of models!
ALWAYS READ THE MANUAL AND CHARGE OUTSIDE IN A SAFE DRY PLACE!!!

Overlander
380mAh 1S 3.7v 25C LiPo Battery for Hubsan X4 FPV/Sonik models - Overlander Sport
$4.79
In stock, 28 units