A wrench for removing the plastic bonnet of a Febco 765 vacuum breaker in 3/4" size. The tool itself normally costs $20-30 but it was simple enough to make. Not all points make contact perfectly at once but enough do for it to work just fine with the leverage it provides.

Before using the wrench I found it impossible to remove this part. I tried everything and ended up breaking off one of the fins so I went and made this instead. After using it the part came off quickly and easily as well as installed without a problem.

I did 4 walls and 20% infill and it worked fine but the wrench did make some noises in use. You could go with a higher wall count if you wanted it to really last.

This model is slightly updated vs the picture shown, I added a some filets to improve strength and also fixed one dimension after the fact.