Enjoy listening to music without tangled cables. These Koss wireless headphones have the over-ear design. They sit comfortably over your ears, but they are still quite compact. Their semi-closed design will ensure clean sound, which sounds amazing. These KOSS BT/330i, Black Wireless Headphones use Bluetooth technology for wireless connection to your devices. Say goodbye to tangled cables. These headphones also have and internal microphone. These wireless headphones from Koss are made with 5.0 Bluetooth. This model can even receive calls. A fully charged battery will last 12 hr(s).