I occasionally have issues getting these jugs open when they've been sitting for a bit, Probably due to swelling of the lid seal.
This wrench fits neatly on the knurling of lid and makes it easy to open when stuck.
If you want the wrench properly fuel resistant i recommend printing it from PETG or PC.
This is the fuel jug: Twenty Rapid Fuel Jug 20L Wit
Don't forget to post a make and give this model a rating, I love seeing those!
The author marked this model as their own original creation.