These are upper spring perches for 2.5″ ID springs if you want to use your stock upper strut bearings instead of race camber plates.
The center hole is sized for 2002, E21 and the like but can be drilled out to fit larger struts (ie. E9, E3, E12, etc.).
Kit comes with 2 perches and some spacer washers. Please specify the year and model of your car so we can supply correct washers. Made from 6061 aluminum right here in the USA.