Sentry Industries Inc. HM431 Flat Folding Stereo Headphones with Mic, Black Adjustable fitting stereo headphones with flat folding design for easy storage, soft ear pads and padded headband Ideal for use with smartphones, cellphones, iPod, iPhone, MP3 player, tablets, PCs and laptops, DVD players, gaming and more Frequency: 20Hz - 20kHz; Impedance: 32 +/- 3 ohms; Sensitivity: 103dB +/- 3dB Drive unit (diam.in mm) - Diameter 40mm; rated power: 150mW 4-feet long cord with 3.5mm plug