JBL Pure Bass sound: JBL Endurance Race 2 earbuds feature 6.8mm dynamic drivers that deliver powerful JBL Pure Bass sound. 48Hrs of playback time, plus speed charging: Enjoy 12Hrs of playtime, plus another three full charges (36Hrs) in the charging case.* 10 minutes on a USB type-C charging cable will give you another four hours of playtime. (*with ANC off) 4 mics for crisp, clear calls: Two beamforming mics on each earbud pick up and transmit your voice while canceling out ambient noise. So you can make clear, crisp calls even when you're jogging through a busy park on a breezy day. Active Noise Cancelling listens to your surroundings & filter out distracting noise. Smart Ambient lets you control how much of the outside world you want to hear, so you can talk with others or stay aware of your surroundings and keep your earbuds in. Enhance your work-out with 'Sports Mode': Use the JBL Headphones app to match your workout with ANC, Ambient Aware and EQ. Choose one of the six default Sports Modes - or you can customize your own.