The Tech 21 Power Engine 60 is an open-backed 1x12, 60W powered extension cab designed to be used with the Trademark 60. It is not a standalone piece; however, it can be combined with any discrete bass preamp. You don't have to tweak your usual settings or presets. Just plug into the Power Engine and go. It has a level control, 3-band active tone control, 1/4" input, and balanced XLR input and output. You can daisy-chain any number of Power Engine 60s together for the really big gigs.