The Hamilton Electronics HA2USB starts with Hamilton's HA-2 headphone and adds integrated USB Sound. Use these headphones with any USB-equipped computer, even one without a sound card! Built with kid's health and safety in mind, these headphones are designed to combat the spread of head lice in schools. Each headphone comes in its own heavy-duty, write-on, reclosable bag. When sealed in the bag, lice is killed in 24-48 hours without the use of chemicals. Specifications: *USB 2.0 Compliant, * Exclusive XearTM Software for reproduction of CD Sound, *Virtual Dolby 5.1 CH Effects, * Compatible with Mac OSX (Latest version recommended), *Compatible with Windows 7, Vista and XP (Latest service packs recommended), * Impedance: 170 Ohms, *Frequency response: 18-20k Hz, * Cord: 2 meters, * Speaker drivers: 40mm Cobalt magnet type. Weight: 5 Ounces. One (1) year warranty.