Optimized 40-mm (1.6-in.) speakers deliver exceptionally powerful, clean sound and the maximum transmitter range is 100 m (330 ft.). a muting feature prevents unwanted noise by automatically muting the headphones if the transmitter signal is too weak. an autotuning function makes the k 305 afc ii very easy to use. to tune the headphones to the transmitter frequency, all you need to do is push a button. circumaural earphones and a self-adjusting headband provide optimum user comfort. a charger and special contacts integrated in the transmitter charge the rechargeable batteries located beneath one of the detachable, washable fabric ear pads. thus, the transmitter is also a charger and convenient cradle for the headphones . the system comes complete with two aaa size nicd rechargeable batteries. the k 305 afc ii is also ideally suited for tv and all multimedia applications.