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. 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. Pure Bass. Zero noise. A simple touch allows you to manage and enjoy perfect calls anywhere, without ambient noises. The light stick open design ensures comfort all-day long and natural sound awareness. Best of all, the JBL Headphones App lets you personalize your entire listening experience. - 32 hours battery life - water resistant & sweatproof - different size sealing tips - Active Noise Cancelling - ambient aware - talk thru Dimensions - Charging Case Weight (g) - 38.6 - Charging Case Weight (oz) - 1.4 - Earpiece Weight (g) - 9.6 - Earpiece Weight (oz) - 0.3 Condition: pre-owned, very good. This brand has a habit of the left earbud disconnecting between uses and the duo need to be paired up again every so often (explanation here: https://support.jbl.com/howto/left-ear-no-longer-connecting-us/000020443.html). Apart from that I really liked these.