40 Hz to 20 kHz frequency response offers full range of deep bass and treble clarity; Soft vinyl closed ear cushions create tight seal around ears and reduce ambient noise; Active noise reduction technology eliminates unwanted low-frequency noise; Fully collapsible design makes headphones ideal for travel; Extra-soft, padded headband delivers lightweight comfort for extended listening sessions; Up to 30 hours of continuous play; Includes 1/4 in. 4 ft. single-entry straight cord and 2-prong airline adapter; Covered under the KOSS(R) Stereophones Limited Lifetime Warranty;