At first I thought it was just a fad that will pass. But I recently had the opportunity to help my family navigate through the airport and public transportation system in Taipei and 4 or more wheels is definitely much easier to handle than the regular 2 wheels.
They call them spinners because you can spin them 360 degrees in one spot showing the maneuverability of their design.
I see eBags now has a sale that is up to 70% off spinners right now through July 4th, so you may want to take a look.
Extra 20% Off + Free Shipping on Orders over $100 at eBags.com!