Part of what makes the Bluebuds X sound great is the use of a custom implementation of the Bluetooth codec called Shift, which greatly reduces the negative sound effects that occur through compression and decompression. If you've ever experienced listening fatigue, Jaybird employs a filtering system called Puresound to eliminate white noise so that the only things sore after a workout are your muscles. For a secure fit, the Bluebuds X comes with ear cushions that offer stability and comfort and never get in the way of what you're doing. With an 8 hour battery life, these wireless IEMs pack enough juice to never let you down.