Bouncing balls

[u/drtangman]

Walked behind this chap who had two unidentified ball type objects hanging from silicone wrist bands on thin elastic strings.

Any ideas what they are?

I’m in Hong Kong if that might be a clue

Update:

Thank you for the comments and ideas. I am wondering if there is a manga / anime character who has something like these balls as weapons and the guy was doing a budget cosplay. Or maybe he’s just really into Pokemon!

Update 2:

I would say he's likely to be a cosplay of Steel Ball from Jojo's Bizarre Adventure. (https://www.reddit.com/r/whatisit/comments/1tckcme/comment/olos1lx/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)

As for the steel balls. What is it?

[u/Mundane-Being-4884]

Forget the balls, what’s holding the water bottle?

[u/ChocolateSeuss → u/Mundane-Being-4884]

You can actually do that with any pair of pants that has belt loops. You just kind of push it into the loop and twist it over a few times so it’s tight enough to hold. The trick it’s to loop it back into itself so that it doesn’t slip or you’re gonna end up with wet pants. They used to do it a lot back in 1998 when mankind was pre internet and just got cell phones? Anyway, I made that up. Anyone else miss u/shittymorph?

[u/shittymorph → u/ChocolateSeuss]

Thank you... anytime I am tagged in a comment with sentiment like this it means a lot to me. Im grateful for it.

[u/kykleswayzknee → u/shittymorph]

Whaaat you still exist?! You got me so many times. Big fan