This is a 3.4 base mount that comes with a plate that attaches direclty to the KX3. The plate connects to the space where the elecraft keyer would be attached. The key connection on the side of the KX3 remains clear so you can plug your key in.
The Height connection can be adjusted between 7.5" to 9.975" high.
The head of the base has a ball that allows for 360 degree swivel.
The base is 7" X 7"