I'd just take it down to the local hardware store and find the nut that fits. As long as you don't confuse course thread with fine thread and booger it up, it shouldn't be too difficult to find the right one. As for installing it on a Gatorade cooler, the manual also says that it is good for sidewall of up to a 1/4 inch. I'd measure the thinnest part of the cooler and go from there, as best you can, drill hole, install. If it's thicker than 1/4 inch, you may have to improvise a little.