Universal Pannier Bag Hook - turn any backpack into a pannier bag

This is a reverse engineering of a product by www.pannierhooks.com, given I don't live in the USA this would have been quite costly to get it imported and an unpleasant experience overall, I have used this with PLA+ and it has been very strong, a single hook could hold 15kg of weight easily, PETG is recommended as the Hook needs to be a bit more flexible to snap onto the pannier rail easily but it still can be done with a PLA printed one. Since printing I have reversed the bolt and nut arr