Hi. This is a Cup Holder Adapter designed to fit all large water bottles, like the 40oz wide mouth Hydroflask/Yeti Rambler. The top screws off, perfect for stashing things like coins or candy inside. You might need to screw it in & out a few times to "wear it in", but it snugs nice. It is not top heavy at all, and it fits in every cup holder I've tried so far. I think everyone should have one. 

If you live somewhere hot like I do, print this out of PETG or something that can withstand the heat. It prints with tiny tree supports that are easily removed by hand. My profile is a PETG profile that prints a bit SLOWER than normal PLA profiles, just keep that in mind.

On a random side note, I have been challenged by @ZachariusAmbifi in direct competition to see who has the superior design, click here to view his design and vote by commenting to let us know which design you prefer!