Xtreamer H1. Device connectivity: Wireless, Device interface: USB, Wireless range: 20 m. Ear coupling: circumaural, Headphone frequency: 18 - 21000 Hz, Headphone sensitivity: -70 dB. Compatible battery sizes: AAA. Dimensions (WxDxH): 133 x 85 x 225 mm, Weight: 310 g, Receiver weight: 280 g. Continuous audio playback time: 20 h, Minimum system requirements: Xtreamer/Xtreamer PRO