Our 22 has the same Clarion that Will C has.
However it is easy to convert any wall wart type of boom box or small speaker/I pod system to 12 volts. I have one by Memorex in the RV, which has an I pod charger, dock on top, I think is 12 volt input (but have to check this PM), and has AM/FM radio, as well as another mini jack input (which I put a Sirius radio into). The 12 volt power supply is easy made with a cig lighter plug, and a radio shack "converter" if it is anything but 12 volts--just get the right "tip" and check the polarity. This little box is about 10" x 4" x 8" (approx) and has decent sound for the size.