Designed with Bluetooth 5.1 chip for improved compatibility and stability. Bluetooth receiver (RX) and transmitter (TX) in one device. Equipped with HD LED digital display showing working status and Bluetooth mode. Built-in decoder chip delivers enhanced bass effect with three-level gain adjustment. NFC function enables quick pairing via smartphone tap. Bluetooth version: 5.1 Supported profiles: A2DP, AVRCP, HFP Operating frequency band: 2.402 GHz – 2.480 GHz Power class: Class II (Power Level 2) Sensitivity: -85 dBm (BER < 0.1%) Signal-to-noise ratio: 90 dB Total harmonic distortion: 0.1% Interface types: Input: 3.5 mm AUX, USB, TF card slot, 6.35 mm microphone input, digital optical fiber, digital coaxial Output: 3.5 mm AUX Supported audio formats: MP3, WAV, WMA, APE, FLAC, G729, M4A, ALAC, DTS, MIDI, G726 Built-in rechargeable battery: 3.7 V / 1200 mAh Charging input: Type-C, 5 V / 1 A Approximate charging time: 1.5 hours Battery life: Up to 8 hours (RX or TX mode) Bluetooth range: Up to 30 meters in open space Compatible devices: Smartphones, tablets, active speakers, power amplifiers, desktop computers, mixers, karaoke machines Product dimensions: 98 x 67 x 24.2 mm Color: Black Material: ABS Package contents: 1 x Adapter 1 x Infrared Remote Control 1 x Charging Cable 1 x Red and White RCA Cable 1 x AUX Audio Cable 1 x English User Manual