Fiction Sprocket Top Hat SpacerThis top hat spacer is specifically designed for a BMX sprocket. It rests inside the sprocket to bridge the gap between the sprocket and the axle. As a result, it stops your sprocket from going up and down when your cranks spin. Genuine Fiction/Stolen spare part. Features: Use: BMX Type: Sprocket Top Hat Spacer Genuine Fiction/Stolen spare partManufacturer's Part Numbers: S579 Silver 19mm S580 Silver 22mmBuy Fiction Components from Chain Reaction Cycles, the World's Largest Online Bike Store.