Ridden by more professional riders than any other wheel, the Root Industries air series wheel is the industry's most popular pick, all at an affordable cost. Root Industries special hollow-core technology places strength and stability where it matters and nothing more. This allows for a good lightweight and robust core. Lab tested and rider approved urethane delivers a smooth ride and a long lasting wheel. Rounding out the air series wheel are elegant finishes and a variety of colour options to make your scooter stand out among the crowd. Features: aircraft-grade aluminium alloy core offered in 110 mm and 120 mm lightweight design ABEC 9 bearing included and installed 88A pu hardness 23. 8 mm width profile 6. 95 ounces/197 grams per wheel (110 mm), 8. 08 ounces/229 grams per wheel (120 wheels are sold in pairs.