Toilet Water Supply Line Wrench

I needed to change our toilet fill valve this weekend, but whomever installed the toilet tightened this nut down so hard I have blisters from trying to remove it by hand. We also have a toilet that is shaped in such a way that you absolutely cannot get any leverage on this nut.

3D Printing for the win!! I took a quick measurement of the nut.. counted how many ribs there were, and quickly designed this and printed it off. It allowed me to get the tiniest bit of leverage and be able to get the nut off and allow me to change the fill valve!