Adam, Yes it is a pond basket. Do you use them?? If not, I recommend it highly. It works just as well, if not better than a 'root maker' nursery pot, and even the training pots with screened sides you will see elsewhere. They help form new "fine" root systems for your bonsai. Guy wiring is a snap using the top row of mesh as your anchor. They are about 3 bucks at home depot for the largest one (13 inch square) and cheaper. Come in rounds, ovals and smaller sizes.
No, I dont work for the pond basket company....
I have about fifteen of my trees in these baskets as of now. Next spring I will repot more into them. I currently use them for larch, hornbeam, amur maples, norway spruce and a large chinese elm. All of them are doing much better than those in my regular pots (nursery pots) with bonsai soil.
Paul