Black, and in 51mm. The skateboard stays as close to the ground as possible without getting into weird sizes: less height for the ollie to pop, less rotating weight on the axles, faster flips.
What makes them different is the 34mm width. For a wheel of this diameter, that’s a lot, and it gives it a contact patch that small wheels usually don't have. In practice, you gain the agility of a low wheel without the instability that usually comes with it. The shape is called V4 Wide for exactly that reason.
100A is the hard extreme. It doesn't deform, slides easily, and maintains speed on smooth ground. In exchange, it transmits everything under your feet, so it’s a wheel for parks and good surfaces.
