These pictures are to help you see the difference in the thread sizes for gun heads (diffusers).
There are only two sizes in the airless industry.
(Binks does use a weird 3/4" thread, but rarely does anyone use Binks airless guns.)
Older (pre 1997-98) Wagner and SprayTech used the 11/16" thread.
Graco, Titan, Amspray, and 99% of all Newer SprayTech/Wagner. (newer meaning guns made after 1998; we say 99% since you can still special order 11/16” thread guns.)
It is pretty simple to tell the difference in the two threads. You should be able to visually tell by using the pictures above. If not, you can use a ruler. Items like tip extensions, tip bases, and such on our website can have a place for you to pick a thread size. Just measure your gun head or tip base to see what size you have.
With all that being said, all the airless sprayers and spray guns we show for sale on our website come with the larger 7/8" threads unless otherwise stated. (and it will be stated in very large letters)