I have for sale a very good working KAF2 audio filter/clock for the K2. The unit comes with connectors and hardware to install the it. The only issue is that I broke the 1/2" standoff used to install the KAF2. I made one using two 3/16" standoffs which worked fine. This item is available from Elecraft. I will ship to your door for $60. Thanks Brent WB4X