The OJ Russell Sexy Mermaid Double Duro 99a/95a Skateboard Wheels is a pro model wheel for Chris Russell coming in at 56mm diameter. The new Double Duro wheels from OJ feature a harder 99a outer and softer 95a core. This makes for a hard wheel that slides and reacts the same as any 99a wheel but with the cushioning of the 95a, has a smoother ride and able to tackle rougher terrain better than the standard 99a wheels.