M8 Hexagon Nyloc Nuts 1.00 Pitch Fine Thread Grade 8 DIN 985 Type T Zinc Plated

A nyloc nut, also referred to as a nylon-insert lock nut, polymer-insert lock nut, or elastic stop nut, is a kind of locknut with a nylon collar that increases friction on the screw thread. 

 Fine pitch nut  are used for all bolting and fastening applications,should be preferred if being used to adjust settings, as they give closer, more precise control