164FT LONG RANGEWith Class 1 Bluetooth technology, the 1Mii Bluetooth receiver can achieve a range of up to 164ft (50m) line-of-sight in open air and up to 50-70ft (20-30m) indoors(without obstacles). aptX HD & aptX-LL & 3D SURROUNDIt features Bluetooth 5.1 chip to ensure high fidelity Bluetooth audio signal for music streaming to those speakers or home stereo systems that doesnt have the capability. It also supports aptX HD and aptX Low Latency (aptX-LL). And the 3D audio can be switched on or off by pressing the 3D button on the Bluetooth audio receiver. The green LED will be on when switched to 3D audio.