Hello Daniel! > If I get these two options; KPA100 et KAT100; I want to put them in the > EC2 case arrangement. Which K2 options must I get from Elecraft... You only need to buy the KPA100, KAT100-2 and EC2. The K2 will need the KIO2 if you don't already have it, so that it can communicate over the auxbus with the KPA100. 73, Lyle KK7P