My irrigation layout left some space behind the sprinkler heads that wouldn't get watered properly, so I designed these sprinkler heads to spray a foot or so behind the sprinkler as well.

You'll need an M5 screw to plug the center (any length... but 12 mm or so seems about right), and you can use the valve seat with it to adjust the flow. I've also included a plastic screw, but it's not really strong enought to work well.

I also included a blank sprinkler head if you want to use it to make your own spray pattern.