Use Califone's Wireless Headphones in computer labs, music class or anywhere that requires lesson flexibility. These wireless headphones allow students to join existing groups who are already using a Califone USB Transmitter system. Up to four students within five feet from the transmitter can listen to and participate in group lessons and activities. Noise reducing earcups with replaceable foam-filled ear cushions help block out external sounds and keep students comfortable. Adjust the headband to fit both children and adults. Does not include USB transmitter needed for independent use.