Used Garmin GTX-327, p/n: 011-00490-00, s/n: 83720690. Sold as removed. The panel-mounted GTX 327 is a TSO-certified Mode C digital transponder. Its innovative features, proven performance and reliability bring a whole new level of transponder utility to your aircraft. Looking for a more affordable alternative? The panel-mounted GTX 320A Mode C transponder features a pilot-friendly design minus the DSTN LCD display.