Anyone give these a try yet?

Those are designed to fit into the ends of a 7/8" handlebar so can't see how they would work. The description saying it's for a Polaris Slingshot - well, someone is smoking crack...

Quote from MBMedic

Amazon.com: One Pair Red 7/8" Handlebar End Rear View Mirrors For 2015 Polaris Slingshot: Automotive

Look sweet....are they functional?

I would imagine if you owned a 2 wheel bike.