Impedance 24 Dimensions 85 x 225 x 133 mm Connector Jack 3,5 mm/6,35 mm stereo Frequency response 22 - 19500 Hz THD, total harmonic distortion < 0.7 % Ear coupling Supraaural Transducer principle Open, Dynamic Weight Receiver: 230 g (inc. Batteries) Transmitter: 200 g Power consumption 65 dBA Operating time 20 h Modulation FM stereo Power supply Receiver: 2 AAA cells-rechargeable Transmitter: 9V bloc SPL for peak deviation 106 dB What's in the box Sennheiser RS 120 Radio Headphone System - Black and Silver