The twelve Nh90 Lead 1994 (r) Spain Exhaust Muffler component parts are all listed in this schematic.
On this parts fiche the Bolt,washer 6x6 is the most specified component.
Some items from this specific schematic: Muffler Comp.,ex., Rub.,protr.pkg. (nas), Collar,muffler, Washer 6mm.