Williams Sound HED 021 Deluxe Folding Headphones, Adult size, Mild and low gain hearing loss rating, 100 mW Max Power Input, Sensitivity 110 dB @ 1kHz, 30mm Driver Size Adult size Mild and low gain hearing loss rating 100 mW Max Power Input, Sensitivity 110 dB @ 1kHz Nominal Impedance 32, Freq. Response 20 - 20kHz 30mm Driver Size, 3.5mm mono plug, 39" cord