Specifications: Speaker Size: 40mm Diameter (1.6 inches) ? Impedance: 32 Ohms, +/- 15%? Frequency Response: 40 H - 18 kHz ? Sound Pressure Level: 100 dB +/- 4dB? Rated Input Power: 20 mW; Max. Input Power: 100 mW? Distortion: 5% Max.? Volume Control: In-line; adjustable ? Cord: Straight, 4 feet ? Plug: Stereo, 3.5 mm Nickel Plated ?Stereo ? Labels: L (left) and R (right)? Ear Pad: Soft Vinyl (Washable) ? Headband: Vinyl with Comfort Sling ? Headphone Cup Noise reducing, ABS plastic for durability ? Weight 6.7 oz.? Warranty: six months Compatible with PC and Mac computers CPSIA TestedChester CreekTM Headphones are seriously good sounding and astonishingly well built, and the soft, comfortable cushioned headband adjusts to fit both children and adults. With clear stereo sound and adjustable in-line volume control, these headphones are a great choice for computer labs and speech classrooms where students, or anyone can reduce distraction from outside sound.