Using 4 super bright led39s a battery and mini usb for charging the guee tadpole 4 led light set provides long lasting performance and excellent value for money this bike light set has a built in interchangable lithium battery which provides at least 1000 times charges with burn times of up to 7 hours per charge the guee tadpole is a perfect communting partner that will last the test of time a complete recharge takes just 1 hour and 40 minutess and battery indicator lights ensure