This is a scale audio stereo - sized and modeled after full size Car Audio systems with the amp mounted (it is removable) to the back of the speaker box. Single wire hookup to any available connection on your RC, or provide other external DC power via a regular 5.5mm plug power adapter that provides DC voltage in a range from 5v to 24v. Choose your connection (see photo).
The amp has a volume gain just like a regular Car Audio amplifier. Set your max volume on your BT equipped device, and increase the amp gain until the sound stops increasing audibly, then back it off 1/8 turn and you'll have it set to last the long haul. Your voltage input will determine the amplifier output and the woofers don't need more than a 5v input will deliver, so for example: you'll need a lower amp gain at 24v, than you would at 5v off an RC receiver. Be aware of this as to not burn up the woofers, or amplifier. Note: while it's styled to look like a "sub box", due to their size they are full-range JBL (harman/kardon) speakers that sound amazing!
They're the same drivers that JBL uses in most of their portable Bluetooth speaker systems, and they do offer some really impressive bass for their size. The sound carries cleanly over great distance, and will make your RC car, crawler, or truck stand out from the crowd anywhere you play. Works excellent in 1/10 scale, but can fit other models. Footprint 4.25" x 3.5" x 2.1. Black is the default color - if a different color is desired, check for availability.