Here is my Hardrock-50 amplifier which I used exclusively with my KX3. Everything works as it should and it is putting out a solid 50 watts (see picture). This one does NOT have the ATU installed. However, I am including the Hobby PCB breakout board for the KX3 and a personal interface I made for using portable outdoors. The ACC1 and ACC2 cables, of course, come with the breakout board. Firmware installed is 3.0. Some superficial scratches. User manual can be downloaded here : https://hobbypcb.com/files/download/4-hardrock-50/8-hardrock-50-operating-instructions I will let it go for $325 shipped CONUS. I accept Paypal only.