This instructable is to show you how to make a wrist strap to hold your Nalgene or similar water bottle. (My First Instructable)
Start by measuring the length of the strap that you want by taking a piece of paracord and looping it around the top of the bottle just below the lip of where the cap goes on. As shown. I used about 2 1/2 ft. of #325 cord. Allowing a little extra for the loop where the snap (or whatever you want to use) can be attached.