FOUND IT.

INSERT-VALVE SEAT (INLET) (STANDARD) AB 111-8021 INSERT-VALVE SEAT (0.13-MM OS, INLET) (0.13-MM OS OD) AB 111-8022 INSERT-VALVE SEAT (0.25-MM OS, INLET) (0.25-MM OS OD) AB 111-8023 INSERT-VALVE SEAT (0.51-MM OS, INLET) (0.51-MM OS OD) AB - 107-0268