If you love variety in your workouts – swim, run, bike, paddle, or surf – then you'll love the TRI Multi-Sport Waterproof Bluetooth Headphones with a built-in MP3 player. We designed these headphones for multi-sport enthusiasts and triathletes! TRI uses H2O Audio's bone conduction technology to deliver clear sound without blocking your surroundings, so you can stay alert as you listen to your favorite music, podcasts, or audiobooks. Enjoy several hours of offline playback with the built-in MP3 player. Add music directly to the TRI by connecting it to your computer using the cable connector provided. Copy your favorite music or podcasts, including M4A, MP3, WMA, FLAC, and APE, and it's ready! To stream from your smartphone or music-enabled smartwatch, simply connect the TRI Multi-Sport Headphones via Bluetooth. Then go out and have fun! Please Note: Bluetooth range underwater is about 4 inches, so your smartwatch must be attached to your goggles (not on your wrist) for Bluetooth to function while swimming. (Wireless range on air is 30ft/10m.) Check out the H2O Audio Smartwatch Clip Mount if you're interested in this feature. WHAT'S IN THE BOX: The TRI Multi-Sport Bone Conduction Headphones come with a magnetic USB charging cable, earplugs for swimming use and an attachment leash. H2O Audio products are submersible to 12 feet (or 3.6 m) underwater. (Waterproof Rating: IPX8.)