Extended Long Range:The Bluetooth adapter uses a dual-antenna design to achieve a line-of-sight range of up to 160 feet (50 m) outdoors and 80-110 feet (25 m-35 m) indoors. Note: Operating range may be affected by physical obstacles such as Wi-Fi routers, wireless TV adapters, walls, metal barriers, etc. and also depends on the receiving deviceTrustworthy After-sales Service:Once purchased, you are our valued customer. If you have any questions or need technical help, please contact us through Amazon message or the contact information in the user manualBluetooth Receiver/Transmitter: M18 Bluetooth Receiver and Transmitter can transmit music from your cell phone, computer or tablet to any of your home stereo system via Bluetooth. It can also transmit music from your TV, computer, projector, amplifier to Bluetooth headphones or speakers (automatic proximity connection), plug and play, easy to useUpgraded Knob & RGB Design:You can use the knob to switch on/off, adjust the volume, as well as the bass and treble control knobs, which can easily handle powerful live sound. Upgraded RGB design, the color changes according to the state of use, full sense of atmosphereWider CompatibilityBluetooth dual-core upgrade, equipped with high-performance DSP and Bluetooth 5.3 chip, clear treble, subdued bass, master tuning. We come with ports for 3.5mm AUX/RCA/optical and coaxial outputs, support for USB flash drives, and a 6.5mm microphone connector, plug and sing, powerful compatibility to meet your daily music experience Note: Optical coaxial is used in transmitter mode