Monoprice 10243 Premium Hi-Fi Over-The-Ear Headphones, Black Drivers - 2x 50mm woofers, 6x 13mm tweeters Woofer Impedance - 50 ohms Tweeter Impedance - 32 ohms Frequency Response - 20Hz - 20KHz plus or minus 3dB Sensitivity - 114dB plus or minus 3dB