Spitfire Provost Formula Four Pro Classic Skateboard Wheels

Standard - Your classic wheel shape, it's not built to excel in specific scenarios like a narrow or wide wheel, but it's appropriate for most situations. If you're new to skating this is where you want to start.

Smooth - Smooth wheels have less surface friction than treaded wheels and are easier to slide.

Formula Four Urethane - Unmatched abrasion resistance for fewer flat spots. More controllable grip. Lasting speed no matter the terrain. Smooth anti-slick slide and a longer lasting size and shape.

Classic Shape - The original Spitfire wheel designed and shaped by the pros who ride them.

99a - Best used in pools and parks with a little more grip than harder wheels, and a little more slide than softer wheels. Ideal for moderately skilled riders who also want to skate street when needed. Hard enough that sliding is a breeze while soft enough for a smooth roll and plenty of grip.

Most urethane skate wheels generally range from 75a-101a, the numbers increase with the hardness of the wheel.