Take open-ear listening to new depths. Swim, run, cycle, and train harder than ever before with open-ear headphones that can withstand all elements. Internal Music Storage Only Not Bluetooth Compatible IP68 Waterproof 8-Hour Battery Life Comfortable Under Swim Cap DESIGNED FOR SWIMMERS Engineered to withstand all elements. Xtrainerz are fully waterproof and submersible so you can swim, run, cycle, or train harder than ever before. OPEN-EAR COMFORT Our open-ear design powered by bone conduction technology ensures bud-free, comfortable listening all day, in or out of the water. 4GB OF MP3 STORAGE Internal music storage allows for a library of up to 1,200 songs ready to play at the touch of a button. Supports MP3, WAV, WMA, AAC, and FLAC for device-free listening. Not Bluetooth compatible. HOW TO UPLOAD AUDIO FILES TO XTRAINERZ Open the USB charging cradle, insert your Xtrainerz into the charger, and close. Plug the USB end into your computer (a Xtrainerz drive will pop up) Drag and drop your fave audio files into the drive