Listen everyone:
Stabilized SP Alps keycaps only work on
a. the Infinity board
b. Certain very cheap keyboards from the 90s, for instance from Chicony, or a few other OEMs, all of which have terrible cases and pad printed ABS keycaps. Nearly all of those use a “bigass” enter key with some totally wacky stabilizer system for it, so it’s basically impossible to get full replacement keycap sets for them, and really not worth worrying too much about IMO.
c. Matias’s upcoming 60%-with-extra-wide-bottom-row keyboard (which should support keycaps with either type of stabilizer inserts).
Any other Alps keyboard you have, e.g. Apple AEK, Dell AT101, Northgate Omnikey, etc., or any other Matias board, or the V60, etc. etc., will not support SP’s stabilized keycaps.
This set is only worrying about case (a) above, but might also be useful for people in the (b) and (c) buckets. For everyone else, this set won’t work for you, whether or not it includes a 2.75u right shift.