AfterShokz Trekz are wireless open ear sport headphones for safety, comfort and premium sound. They use bone conduction technology that transmits audio by sending vibrations to the inner ear through the bones in one’s cheek. Unlike sound waves that travel through the air, bone conduction bypasses the eardrum, yet delivers the same sort of nerve impulses to the brain to be recognized as sound. This headphones feature Bluetooth 4.0, an internal battery good for six hours of play per full charge and a titanium frame that helps to keep it lightweight, durable, and flexible.