Bones STF 99A V1 Skateboard Wheels 54mm The Bones STF 99A V1 Skateboard Wheels are built for street skating with a fast, controlled feel and dependable slide performance. Bones Street Tech FormulaA(R) is designed to grip when you need it, slide when you want it, and resist flat spotting for longer-lasting performance. The 99A Easy Streets(TM) durometer offers more control and softer landings on rougher terrain compared to harder STF options. A smooth surface and V1 shape round out a versatile street setup. Details Diameter: 54mm Width: 32mm Durometer: 99A Formula: Street Tech FormulaA(R) (STF) Shape: V1 Surface: Smooth Suggested Use: Street Color: White Performance: Fast rolling with controlled grip and slide, plus resistance to flat spotting