Where to rent 4K DVD's?

I have a new 5.1.4 home theater system. I was renting Blu-Ray disks from Netflix. They told me they will not be renting 4K disks. Red Box does not have 4K disks where I live. 
Are there any mail order options available? Thanks
@thyname Thanks for the comment. I just checked the website and its exactly what I am looking for. Thanks again
Redbox has 4K disc for rent.
You are welcome @galleybob
@caphill Redbox does not rent 4K where I live
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You can also try https://rent4k.com.

Never tried them personally since I'm in Canada and they don't ship outside of the U.S. at the moment :(

Maybe give them a try and see how it goes? Good luck!

@superkatt I signed with them. So far so good