The AfterShokz Sportz M2 are bone conductive headphones designed for use by people with hearing and other disabilities. These lightweight, water-resistant headphones fit around the back of the head and rest in front of the ear, delivering stereophonic sound through the user's cheekbones to the inner ear. This permits the user to hear ambient noises such as oncoming traffic, car horns and other warning noises, while listening to the headphones. These headphones have a 3.5 millimeter (mm) gold-plated standard connector that fits all smartphones, iPods, iPads, and MP3 players. They also have an on/off switch, a volume control and a 130-centimeter cord. A water-repellent storage tote is included. POWER: Rechargeable lithium/ion battery with 12-hour playback time and a micro USB charging port. WEIGHT: 45 grams. WARRANTY: Limited 2-year warranty.