Reddit reviews Wilson US Open 9" Jumbo Tennis Ball - Yellow
We found 1 Reddit comments about Wilson US Open 9" Jumbo Tennis Ball - Yellow. Here are the top ones, ranked by their Reddit score.
Larger version of the US Open tennis ballGreat for promotional use, autographs, or just for fun9” Jumbo Tennis Ball
Alright I found the ball: https://imgur.com/wB58ItG
Usually when he's done playing with it it's just a little more inflated than the ball in OP's video, and the picture I linked is about how full it somehow magically fills itself back up.
No promises on this magic happening on any subsequent giant tennis balls or anything obviously.
It looks like it used to say "US OPEN" on it so I'm fairly certain this is the one: https://smile.amazon.com/Wilson-Boxed-U-S-Jumbo-Tennis/dp/B000LPW2UU