JBL Pure Bass Sound: Smartly designed 12mm drivers enhanced by the stick form factor deliver JBL's Pure Bass Sound so you'll feel every pulsing beat. Active Noise Cancelling with Smart Ambient: Hear more of what you want, less of what you don't. Active Noise Cancelling technology with 2 microphones lets you minimize audio distractions. With Ambient Aware, you can tune into your surroundings at any time so that you feel safer when you're out in the world, while TalkThru lets you stop for a quick chat without having to remove your headphones. 4 mics for perfect calls: Enjoy hassle-free, hands-free calls in stereo. The Tune Flex are equipped with 4 microphones, so you'll always be heard with perfect clarity. Never hesitate to take or make a call again. And with VoiceAware, you can choose how much of your own voice to hear by controlling the amount of mic input routed back into your earbuds. Up to 32 hours of battery life: Never miss a beat with 32 (8 plus24) hours of battery life or 6 hours, plus 18 hours in the case when noise cancelling is engaged. Need a boost? Speed Charge for just 10 minutes to get 2 hours of playtime. Water resistant and sweatproof: Don't be deterred by bad weather. Thanks to IPX4 water resistance and sweat proofing, there isn't a workout or downpour the Tune Flex can't handle.