It came with the board with dual pot connected as well as 3 mounting brackets fastened to the board (no screws for mounting to the chassis) and a set of instructions.
Installation was pretty straight forward with a total of 6 wires to connect and drilling the hole for the pot.
About the only thing I can complain about is the quality of the knobs. They needed some fiddling with to prevent the inside knob from rubbing against the outer plus the inside knob was REALLY loose on the shaft and required some epoxy to get it to hold. Very cheezy... The instructions were pretty straight forward with pics of the echo board although there were no specific instructions relating to any particular radio brand.
I have a swing kit and variable DK on my radio and the board had no effect on my output or my variable DK although there have been reports of this board raising DK. About the only thing I noticed was that it would feedback if the mic gain and echo level were both set high. Lowering my mic gain stopped the feedback.
Here's a recording of it transmitting through my little Cobra from about a mile and a half away.
I'm a noob but I couldn't find much info on this echo board so I figured I'd share what I found.