I just made one of these with a corny keg liquid post. Turns out, it's pretty easy. There are 2 green pieces on the nozzle. Take off the first one and pull out the clear plastic piece. Then you can screw the post directly on to what's left. You will be making your own threads with the post and will need a wrench to force it on. The fit is good. To hold the poppit in position, you'll need to use a hack saw to cut off a piece of the green protruding part that the first green part (that you took off) screws into. I took off about a quarter inch. It depends on how far you screw the post down, so maybe saw off a little bit at a time to get it right. Works great, you don't need a coupling or washers. Just $7 for the Flow-Master 56HD and the cost of the post.