New crankshaft inner pulley guide plate, Mazda MX-5 & Eunos Roadster mk1 1.6 (early cars 1989 to Sep 1990).  It is the thin metal plate that goes between the guide plate with the rubber edge and the timing belt drive pulley.

Mazda part no. B630-11-414.

Note that this is for the early 'short nose' or 'LWSC' engine, it will not fit later cars with 8-slots in the outer pulley.

NM01171.  B63011414.