Smooth - Smooth wheels come with a shiny coating on the riding surface that feels grippy at first, but wears away quickly.
X Formula (XF) - XF X-Formulas roll over rough terrain like softer wheels do, but slide much like a harder wheel will.
99a - Offers more grip than harder wheels and more slide than softer wheels. Great for slick surfaces when you want more control.
Made in the USA - Poured in Santa Barbara, California.
