The item exists but while Micro/Small/Medium/Large Amarr Cap Boosters are purchasable in some of the Amarr LP Stores, for whatever reason the Nefantar Store offers Large, Medium, Small - but not Micro.
Seems a little obtuse so would like to suggest they're (re?)added to the LP store, particularly given the lack of T1/T2 supply. The Ammatar stores have copies of everything else (afaik) available to the Amarr and offer a great alternative to those of us with high Minmatar standings.
Thanks for reading