New alternator adjuster bolt, Mazda MX5 or Eunos Roadster 1.8 mk1 and all mk2 & mk2.5 models.
This is the 80mm long adjuster bolt that is threaded through the spacer block to tension the alternator multi-rib belt. Note that this bolt has a 13mm head as opposed to the original 12mm head.
NM01129.