Hi Wes: Actually for what it is worth, the board inside are Trimble Boards with a Trimble oven. I have also corresponded with Leo on his 2 GPSDO units. I like the fact that he says I will have no problem using the unit with both of my K3's. Tnx Wes 73 De Mike VE3YF http://www.ve3yf.com [http://www.ve3yf.com/]