Mi3 wheels provide an alternative to G13 and MaxG. Mi3 wheels were developed with a slightly offset solid spoked core, rather than the traditional hollow core, providing the necessary amount of stiffness, while still leaving some flexibility for that extra snap at the end of your push.
The outer tire of the Mi3 wheels is made out of G13 Polyurethane. The Mi3 wheels come with an core, similar to that of the G13 TR3 wheels.

Matter wheels from USA uses the Footprint scale, the F1 stands for footprint 1.

F1 - equals approx. 85A
F2 - equals approx. 84A
F3 - equals approx. 83A