What do Hubstacks do? What are they for? Do I really need them when I get an all metal yoyo?
Thanks
Hubstacks are bearings at the side of a yoyo with something you can grab. This makes the player able to literally grab the yoyo by its sides.
You don’t “need” hubstacks when you buy a metal yoyo. They are just for fun and you don’t see them in play at a lot of professional performances.
What all can you do with them? (I know what they are and I’ve seen them, but I just don’t know what they’re goo for)
You can grab them while the yoyo is spinning. You can pull start the yoyo aswell.
Example here.
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Here’s a video utilizing hubstacks:
awsome example, is that you in the vid logan?
No, that’s someone else 
Yea, the guy in there looks about 7 years older than me o.O
Can you install Stacks on other yo-yos besides YYF?
The Axiom, Project, and Freehand Zero are able to take stacks, however there aren’t many others that can.
So if I buy a blood red Superstar with translucent hubstacks, can I take them out and put white ones in?
Yes.
Add a meteor in there, there is an axle hole there, same size as the axiom. Just have to remove the caps first.