NAB-701416 - MX-5 Oil Pump Plug
Genuine Mazda® part, oil pump plug.

This plug has to be installed new when changing oilpumps or you will have to reuse the old plug from the old pump.
Reason for this is that Mazda® uses this oil pump on several models, and on some models this hole is used as entry point for the oil dipstick.
2,39 €