
57 & 59mm Wheels.
quoting m1urethane.com:
The Trinity is the first truly innovative wheel skating has ever had. The inner core is made of a new high heat high impact material to eliminate core stretching, stress cracking, and breaking. The middle layer is a softer 68c urethane that will give the grip, feel, ride quality, and impact absorption of a softer wheel.
The outer layer is made of our newly proven pro urethane in a 91a but is does not feel or ride anywhere close to that hardness. With having a softer inner layer it adds surface pressure to the face of the wheel to allow us to raise the hardness in the outer layer to increase the durability and speed of the wheel without compromising any of the ride quality or giving a hard feel to the wheel.
Finally we have the most important part of the wheel, the sidecut technology. It helps the wheel by reducing the weight of the wheel by about 15% and allow the wheel to flex enough to allow the wheel to get maximum amount of grip from edge to edge.
Thanks Jack & Wally.