Hey man,
Root pruning containers which I do not recommend for large growing trees. They’re great though for hardwood/softwood cuttings and tomato plants or pepper plants or flowers etc. Here are a couple of my favorite sellers:
This is the ultimate starter pack. It won’t get any better than this. I spent days on the internet researching:
https://www.amazon.com/gp/product/B078N75MG8/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
And the 22 cm x 20 cm from this seller is as large as I’ve found w/o going to root pruning gallon containers made of denser fabric/again I’ve done hours of research (20 x 22 = 1/2 gal./2 qt. container) :
Dax