1. Bluetooth version: V5.4 2. Frequency range: 2.4GHz (2402-2480MHz) 3. Support protocol: A2DP, HSP, AVRCP, HID, etc. 4. Transmission distance: 20M (open and unobstructed distance) 5. Rated voltage: DC 5V 6. Interface type: USB 7. Operating system: Windows 8.11011 system 8. Dimensions: about 23.8 x 15 x 7.2mm 9. Note: only the adapter, does not include other items in the picture Features: 1. Bluetooth 5.4 chipset, faster transmission speed, more device connections, more stable transmission conditions 2. Compatible with multiple Bluetooth versions, automatically backward compatible with Bluetooth devices 5.35.25.15.0 and below 3. Wide range of compatibility, support multiple devices connected to Bluetooth at the same time 4. PC connected keyboardmouse, wireless operation 5. PC connect audio, wireless listening, support multi-device connection, no delay, mobile bluetooth, stereo HD sound 6. PC connected Bluetooth headset, enjoy the freedom of wireless music 7. Built-in wireless signal enhancement, to achieve 20 meters barrier-free long-distance transmission, stable and smooth connection, refused to intermittentdisconnected connection