Sector 9 Longboard Wheels Nineball 70mm - Dark Blue - Nineball Skateboard Wheels by Sector 9 offers size, strength, stability. 70mm, 78a durometer. Great for Longboards. These skateboard wheels are the best for manueveralbility and smooth speed, low center of gravity for maximum balance. sold in sets of 4. Features - Super Smooth - Long-lasting - Won't chunk out - Good for pools, parks, hills, and shredding concrete. - Urethane hub