Please Read - Floating Spacers are used when you have 8mm (same size as bearings) axles. These go in between the bearings which Precisely aligns wheel assembly for speed & true spin. Made with structural aircraft aluminum for high strength & durability. Dissipates heat buildup – radiator for your skates. Dampens vibration & noise – shock absorber for your skates. Fits standard 608 bearings with 8mm axles. Includes 8 spacers.