ACE H80. Device interface: USB, Frequency band: 2.4 GHz. Ear coupling: supraaural, Headphone frequency: 20 - 20000 Hz, Impedance: 32 Ом. Battery technology: Lithium-Ion (Li-Ion). Mac operating systems supported: Mac OS X 10.5 Leopard, Mac OS X 10.6 Snow Leopard, Mac OS X 10.7 Lion. Cables included: USB