Product Description The PMX80 Behind the Head Ear Speakers uses Vertical Ear Speakers and pumps rich audio comfortably into the ear. They are compatible with MP3, iPod and other portable devices with a 1/8 inch connector. The neck band system floats the ear bud for long lasting comfort. Sweat-proof coating wicks moisture, enhancing durability. Neck band features a reflective rear for safty when running at dusk. All Sennheiser Sport Series carry a 2 year warranty. Specially designed Neck Ban with Vertical Transducers for best fit. Powerful magnets for detailed sound. Reflective strip for extra visibility at dusk Sweat and water resistance.