Bloob Fingerboard Wheels are made of a 70D Resin, which have a hybrid feel between plastic and urethane. They're responsive and hard, but still give you a good amount of grip. A single, pre-installed ABEC-9 bearing is installed to keep the wheels spinning smooth and fast.
The 84s shape is a scaled up version of the 80s, which is a more compact design of bowl wheels. They use a conical shape, and come in at 8.4mm x 6mm.