Denver TSP-402 is a trolley speaker with a built-in battery that offers a variety of features for playing music and making announcements. With its 40W power output and 8-inch speaker, it delivers clear and powerful sound. Connect your devices via Bluetooth, USB, SD card, or AUX input to enjoy your favorite music. Record and playback audio using the built-in recording function. Control the music and adjust the volume, treble, echo, and microphone volume using the control panel or the included remote control.