PRO Brick Wheel - Axle Assembly for LEGO Derby Car Racing (set of 4) from Pinewood Pro Derby Car Wheel Assembly includes 4 PRO Bricks, Wheels and Axles assembled and ready to snap onto any LEGO part Lighter Wheels = Faster Speed Nickel Plated Axles = Faster Speed PRO Brick gives you perfect wheel spacing for racing LEGO Derby Cars down a pinewood derby track Custom engineered Axles are polished and nickel plated to minimize friction