This spacer is used in Roces FCO and M12 skates that have 6mm diameter axles.
They are a perfect upgrade to oldschool Roces skates that come with white nylon bearing spacers. Buying these will make your skate faster and more responsible if you swop the nylon spacer for these brass spacers.
Do not buy these if you have any other brand skates because it is very likely that they will not fit. Roces Axles are slightly thinner then the standard 6.3mm axles used by other models. so these bearing spacers will not fit over the axles of any other brand.
The bearings spacers are sold per pcs.