[2-IN-1 SPEAKER & FM TRANSMITTER] Use the Roadtrip as a Bluetooth speaker for calls, voice assistant activation, or directions, or use as an FM transmitter to stream audio from your phone to your car's stereo via FM. [CRYSTAL CLEAR CALLS] Hear every conversation clearly with dual 3W speakers, and ensure your voice is heard just as clearly with the built-in noise-reducing microphone. [HIGH-DEFINITION SOUND] Despite its compact size, the Roadtrip’s dual 3W speakers deliver powerful, high-definition audio with emphasized clarity. [SMART AUTO POWER] The Roadtrip automatically powers off as you leave the car and your phone disconnects. When you return, its built-in motion sensor detects your presence, powers on, and reconnects to your device as you open the door. [EASY TO USE] Turn the rotary dial to adjust the volume, or press it to activate your phone's voice assistant for hands-free calls, texts, and more.