Review on Weller 7250W Standard Solder Tip Replacement (5.5mm) - Compatible with D550/D650 Solder Guns (2 Pack) by Marcus Curry

There appear to be 2 different models of the D550, each with different specifications. But NOWHERE on the information page there is no indication of this. So when they say "Fits D550" they mean 7/16 bore nuts, NOT 5/16. Obviously these attachments do not fit the 5/16 model. WHY the company used the same model number for two different soldering guns is beyond me. And the person who created this page DID NOT KNOW that there are two different versions of this model number? Uh... apparently not.