Opus Bluetooth HeadphonesFully padded Bluetooth headphones which produce crystal clear sound and are compatible with mobile devices that support Bluetooth. They have a continuous playing time of six to eight hours andhave a built in microphone which allows the user to answer incoming phone calls. The volume and track can be changed directly from the headphones, and they can be recharged from any USB port or a mains adapter. Opus is nicely presented in a convenient carry case