They are extra rubber pieces that go on the wheels.I just got the Hayward AquaVac 650. The manual does a very poor job of describing the unit. I'm guessing the bag with rubber circles are extra wheel replacements? Would be nice if they mentioned them. My old Aqua Shark spent more time upside down and on the drain and had quit cleaning the pool. I had to hard brush the pool as the AquaVac 650 was not getting the green off. It seems to be doing a good job now. I will post more as I use it as it's one day old.
The 650 will not clean algy or other fine debris. You will have to clean that by hand.
Read my review or watch the video I made to see what it will and won't pick up.
The one touch canister empty is nice though.