Koss SportaPro Stereo Headphones
The Koss SportaPro portable headphones offer portability, flexibility,  and a headband designed to be worn either atop or behind the head. Equally well  suited for use at work or on a jogging trail, the SportaPro's open, foam-covered  ear cups allow for ambient environmental sounds to be heard, which can be  helpful in a recreational environment.The SportaPro's weight is a mere 2.2 ounces, and the headphones boast a  frequency response of 15 to 25,000 Hz, delivering (on paper, at least) quite a  bit more bass than most home speakers can. Impedance is 60 ohms, with less than  a 0.2 percent distortion and sensitivity of 103 dB SPL (with a 1 mW signal).The SportaPro stereophones are collapsible and come with a carrying case, as  well as both 0.125-inch and 0.25-inch jacks. Koss covers the headphones with a  lifetime warranty.