Features: Transform your non-Bluetooth Headphone into Wireless Headphone. The adapter with built-in Micorphone and Volume control. Compatible for QC15 audio headphone. Boot: Long press the answer for key to boot, until hear the starting up prompt tone (voice prompt boot), then the blue light flashing. Shutdown: Long press the answer for key to turn it off (voice prompt to turn it off). Battery Charging: When charging, the indicator light turns red, the blue light turns means full charge.VOL+: Long press the VOL+ for key to increase the volume.VOL-: Long press the VOL- for key to turn down the volume.Switch to the previous song: Short press the Vol- for key turn to the previous song.Switch to the next song: Short press the VOL+ for key turn to the next song.Music play: short press the answer for key.Music pause: short press the answer for key.Answer/hang up the phone: Short press the answer for key.Re-dial: press twice the answer for key can re-dial the last for time calling phone number. Specifications: Material:PVC Color: Black for QC15 Headset Charging voltage: 5V Charging Current: 200MA Bluetooth-compatible Version: 4.1 Battery Capacity: 120mAH Support Bluetooth-compatible Protocols: HFP v1.6, HSP v1.2, A2DP v1.3, AVRCP v1.5, SPP v1.2 Audio performance: Support SBC, MP3, AAC, Stereo. Transmission Range: within 10 meters (barrier-free) Note: Please allow 1-2cm errors due to manual measurement,pls make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Bluetooth-Compatible Adapter 1x USB Charging Cable