#4-40 18-8 Stainless Steel Coarse Thread High Crown Acorn Nuts (10 pcs.)

Diameter: #4
Diameter 2: 9/32"
Thickness: 3/8"
Material: Stainless Steel
Driver Type: 1/4" Wrench
Thread Size: 40 (Coarse)
Shape: High Crown Acorn
Hardness: 18-8
Type: Cap Nut

Box of 10.

A closed nut having a dome-like cap over the back, protruding part of the engaged screw or bolt. Also called an acorn nut.