#10-32 18-8 Stainless Steel Fine Thread Serrated Lock Nuts (15 pcs.)

Diameter: #10
Diameter 2: 7/16"
Thickness: 3/16"
Material: Stainless Steel
Driver Type: 3/8" Wrench
Thread Size: 32 (Fine)
Hardness: 18-8
Style: Serrated
Type: Lock Nut
Flange Diameter: 15/32"

Box of 15.

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