KOSS 184747 SB45 Full-Size Over-Ear Communication Headphones Delivers high-sensitivity & reduced distortion; Ideal for gamers; Features anisotropic ferrite magnets; Freq resp: 18Hz-20kHz; Oxygen-free copper voice coils improve signal transmission & conduction for a clearer & louder sound; Closed earcups; Soft earpads reduce pressure for long-lasting comfort; Clear Voice Technology(TM) (CVT) eliminates excessive background noise for better voice quality; Foldable; Limited lifetime warranty;