3 Lithium Ion batteries required.

JBL Pure Bass Sound: Get the most out of your favorite workout playlist with rich bass from a 10mm dynamic driver that delivers bold sound when you need it most.
Up to 50 total hours of playback with speed charge: Whether you measure your energy output in miles, pounds, or minutes, the JBL Endurance Peak 3 can match you beat for beat, with up to10 hours of battery power in the earbuds and 40 in the case. And when you need a boost, speed charge up to an hour of playtime in just 10 minutes.
IP68 dust and water proof: An IP68 rating means the JBL Endurance Peak 3 earbuds are ready for your most active adventures, rain or shine. And they’ll endure for 30 minutes at depths up to 1.5 meters of salt or fresh water. So you can surf with your earbuds, or rinse them after a workout, all without missing a beat.