7/16"-20 Zinc Grade 2 Nylon Insert Lock Nuts LKNUT-110 (10 pcs.)

Diameter: 7/16"
Diameter 2: 23/32"
Thickness: 21/64"
Material: Steel
Finish: Zinc
Driver Type: 5/8" Wrench
Thread Size: 20 (Fine)
Hardness: Grade 2
Style: Thin Pattern Nylon Insert
Type: Lock Nut

Box of 10.

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