I got two MX-300's when a friend did an avionics upgrade. They were both working fine when removed. They come with trays and the back connectors. One is missing a knob. I'll sell outright if somebody makes a good offer, but what I'd really like to do is trade these two radios for one TKM MX170B. I've got the old KX170b in my plane and would like to find that plugin replacement instead of paying to have the wiring all changed over for one of the MX-300s. So two radios for your one, win win for everybody.