HV special nuts as per drawing in attachment M6 Material: steel swch35k Plating: PFZn-5C color gray, thickness min. 5µm Follow the tolerance and thread design specification: ISO 68 and ISO 68-1 Follow the ISO 898-2 (mechanical properties of fasteners) made of carbon steel and alloy steel Class 10 Tolerance class 6H Proof load: 20,900N Durezza: 26-36 HRC 2.000.000 pcs. yearly for next 4 years