JVC HAW300RF 900mhz Wireless Headphones (Discontinued by Manufacturer) 900 MHz wireless transmission, 328-foot range; wide (28 to 17,000 Hz) frequency response Large 40 mm diameter diaphragms for full-bodied sound Self-adjusting, comfort-fit headband Rechargeable power supply with Ni-Cad Batteries included Voice Call function for convenient communication between the base and the headphone