Sector 9 Race Formula Dual Durometer Wheels 74mm/80a Out 85a In. Sector 9 Dual Durometer Racing Wheels are designed so that the harder durometer is on the axle-side of the wheel and the softer durometer is on the rolling surface. By having a slightly harder durometer on the inner level of the wheel, the wheel will keep its shape more during hard turns. A must have for any longboard race enthusiast. Features - Size: 74mm - Durometer:80a Out 85a In - - Sold in sets of 4 - Bearings and spacers not included.