Audio-Technica ATH-SR30BTWireless Over-Ear Headphones, Charcoal GrayThe ATH-SR30BT wireless over-ear headphones deliver the exceptionally pure audio of Sound Reality in a convenient wireless design. With exclusively designed 40 mm drivers and a dual-layer isolation housing structure that optimizes phase and transient response, you'll enjoy powerful, full-range audio reproduction from a Bluetooth wireless signal. What's more, the internal battery provides a remarkable 70 hours of continuous use on a full charge.