With the standard pump around 14x9.
With the larger pump the way I hooked it up around 18 or 19 x 9.
I hooked it up by running a piece of flex PVC to the body of the skimmer. It could be done nicer, but I didn't want to mess with it. I am using the pump that came with it on a different skimmer, but if you would want the stock pump instead knock $20 off the price. It skims much better with the bigger pump though.