Price is $1 each, $4 for a set of 4.

These are steel bearing spacers to fit most trucks (8mm axle), and most wheels (0.4" bearing spacing).

Bearing spacers are an optional component used in between bearings to keep them properly spaced apart with minimal play, and allows one to fully tighten down the axle nut.

Some believe the use of proper bearing spacers will make slides smoother and increase the life span of bearings. Others believe they are useless, and wheel play is not an issue if the axle nut is tightened properly.