7/8"-9 Black Phosphate Grade 2 Steel Coarse Thread Nylon Insert Lock Nuts

Diameter: 7/8"
Diameter 2: 1-7/16"
Thickness: 1"
Material: Steel
Finish: Black Phosphate
Driver Type: 1-5/16" Wrench
Thread Size: 9 (Coarse)
Hardness: Grade 2
Style: Nylon Insert
Type: Lock Nut

Box of 26.

A lock nut is a nut that resists loosening under vibrations and torque.