Over on the Big Bad Toy Store, you can find an exact replica of the movie prop, complete with decorations and Mattel brand placement. The 28” x 8” x 3” hoverboard (at least in name) has been deemed official by Universal Studios and is being sold as a collector’s item, for whatever that’s worth to you.
By the way, if you weren’t sold yet, there are whoosh sound effects, which should clinch pretty much any undecided sale.
The Back to the Future Part II hoverboard replica is selling now on the Big Bad Toy Store for about $195. All you need are those replica Nikes that came out a while back, and you’ll be all set. Good luck.