On Dec 9, 8:58*am, Richard wrote:
Trig TT21 Class 2 Mode C Transponder with Built-in Altitude Encoder
$2095

If you compare to the 35,000' * * * $700 to $800 Less

Right, but you can buy the TT21 for a lot less than that if you shop
around. Trig has a minimum advertised retail price policy but some
vendors are selling much lower. It's the old "put one in the order
basket to see the real price" trick.

Check Aircraft Spruce as an example.

Andy