Garmin used GTX 320, p/n: 011-00259-10 s/n: 83500726. Sold as removed. The GTX-320 is a full-featured, compact, panel-mounted Class 1A transponder. The GTX 320's solid state transmitter provides 200 watts nominal power output, eliminating the need for a cavity tube that can degrade with time, fail, or require expensive replacement. 100 percent solid state also means no warm up time, reduced power consumption, and heat for longer service life. Extensive utilization of surface mount technology provides shallow depth and light weight which simplifies installation in the tightest spaces. 14- or 28-volt operation is available without the requirement for external voltage converters or dropping resistors.