Features: brand new and high quality Ring-shaped guide ring design, the guide ring lights up red when charging, and lights up blue after successful Bluetooth-compatible pairing, which is more intuitive to reduce customer complaints about Bluetooth-compatible pairing. Add a voice button. When the user is in driving mode, press the voice button to easily activate the "Siri" intelligent voice. The up/down button is designed on the side of the fuselage, which is convenient for users to control the up and down of Bluetooth-compatible music when driving. Using the latest Bluetooth-compatible 5.0 chip, high-sensitivity microphone, CVC noise reduction technology, longer transmission distance, DSP signal processing technology for clearer calls. Built-in 300mA battery, longer battery life. Specifications: Product model: C28 wireless audio receive and send combo Product color: black Bluetooth-compatible version : 5.0 Battery capacity: 300Amh(battery included) Working range: 10m (without obstacles) Charging time: 1h Use time: 4h Size: approx. 5.5x3.5x1.3cm/2.17x1.38x0.51in Suitable type: computer, TV, projector (transmission mode) / speaker, earphone (reception mode) Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1PC x Adapter