1. Receiver/Transmitter, Seamless Switching, Perfect Compatibility with Wide-range Devices, Receiver (RX Mode), Receives Bluetooth signals for wireless music transmission. Connected Devices: Bluetooth speakers/regular headphones/cars. Transmitting Devices: Mobile phones/tablets/laptops. Transmitter (TX Mode). Connects to audio output devices to transmit Bluetooth signals. Receiving Devices: Bluetooth speakers/headphones/earbuds. 2. Receiving Mode: Wireless Convenience, Free from Traditional Cables, Connect to Bluetooth speakers. Connect to car audio systems. 3. Hands-free Calling for Safe Driving, Built-in microphone enables clear hands-free calling, enhancing driving safety. 4. Transmitting Mode: Wireless Audio, Connect via a 3.5mm jack and transmit audio wirelessly via Bluetooth. Wireless enablement for fitness equipment. Wireless enablement for . 5. Dual-device Connection, Supports simultaneous connection to two devices. Note: In receiving mode, only one device can simultaneously. Bluetooth 5.4: Lower Latency, Enjoy stable, smooth signal transmission with extremely low latency. Power Display & Long Battery Life, 300mAh battery provides prolonged battery life. 10m Transmission Distance, Reliable, obstacle-free transmission range ensures stable and consistent signal. Mini Size & Compact Portability Color: Black Material: ABS+PC Package Contents: 1 * Bluetooth adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.