Bluetooth receiver: UGREEN Bluetooth adapter 5.0 is designed for non-Bluetooth car/home stereo system with 3.5mm aux port. 10m barrier-free transmission. The back clip allows this adapter to stay wherever you want. HiFi sound quality: Stable transmit and receive Bluetooth signals. CSR chip for more stable, faster transmission and lower power consumption. Hands-free function: Built-in microphone supports hands-free calling. The Bluetooth receiver has a switch button and two volume buttons. The volume buttons not only control the sound but also switch the song. Built-in battery: Fully charged for 2 hours, 4-5 hours of continuous use. The Bluetooth receiver can pair two devices at a time and can switch between them freely.