PGP Gear-Drive Rotor Sprinkler with 3-Gallon Per Minute Nozzle

It is 3/4".

It comes with a special key. You insert the key into the top of the head to make the adjustments.

The center area pops up when the water turns on.

I like to do up to 4 heads

I have both red & blue. It looks like each nozzle can be chosen to match your particular conditions such as water pressure, distance needed, and amount of flow. I didn't see any nozzles listed online by themselves but local store may have them available as another local store does sell them that way.

The sprinkler head does not have a check valve - that should be a part of the larger system plumbing.

The nozzles differ by water angle and flow rate. You can see the actual difference on the Hunter website.

The sprinkler head doesn't really have a "distance" adjustment, but it does allow you to select/adjust the rotation angle it covers. The min is 40 degrees and the max is full 360.

That's a NO NO! Never mix Rotors with stationary Pop-ups, always put on separate zones, pop-ups spray constantly over the same area, Rotors spray over a large area back & forth! ALSO if you're trying to cover more area, you can't just ad more heads or even put larger nozzles in the pop-ups, AS IN, if your zones are maxed out on GPM's for the system! Say you have 6 pop-ups with 12FT half sprays and they just aren't quite covering but you go put in 15Ft nozzles, they're 2 GPM each! you'll get less coverage because you're now oversized ! 1GPM x 6= 6 GPM per minute, 2GPM X 6 = 12 GPM 1 This is an example, not an etched in granite! I've been to MANY repairs where they had 12GPM systems and they installed a few 2GPM over 1 GPM heads trying to get more coverage when they're actually making it worse because of pressure drop by adding more GPM to an already peaked out system!

The ones I purchased were equipped with the 3.0 gal flow rate. The nozzles can be easily changed for whatever flow rate (watering amount) each section of your lawn needs.