Bluetooth Version 4.1 with CSR8645 chipset and apt-X, ensure high-fidelity stereo music and crystal clear conversations via noise reduction. Ergonomical design - The in-ear earbuds are designed for a secure fit and premium sound; Magnets allow the two ear buds to attract each other, forming a necklace on your neck to avoid falling down during exercise. The Sleek and simple profile make it easy to answer calls or switch between your favorite tunes on the go. Sweatproof design ensures stability and comfort when running, hiking, camping, biking, skiing, jogging, climbing, doing fitness, etc. Built-in rechargeable Lithium-Ion battery lasts up to 6 hours of talk / play time or 200 hours standby, universally compatible with most Bluetooth-enabled phones, tablets and other Bluetooth devices.