My original water bottle's neck ring that connects the main body to the cap got damaged, introducing the cap to the very real possibility of getting lost!

I designed this very simple and fast 3D print that is surprisingly strong and flexible with PLA+. It is a very tight fit that will make sure that you will not lose your cap ever again (granted you have the same bottle design as mine). 

Print Time is really fast, infill does not matter since it is so thin.