Nylock Nut, Zinc Plated Class 8 - M16 Standard Thread
Nyon Insert Hexagon ISO Metric Locknut, Type-P, Property Class 8 - 800 MPa Proof Load Stress.
ISO general-purpose metric screw threads ("M" series threads) are defined in international standard ISO 68-1. Each metric ISO screw thread is designated by the letter M followed by the value of the nominal diameter. Standard "coarse" pitch listed in ISO 261.