5/16"-18 Polished 18-8 Stainless Steel Coarse Thread Acorn Nuts

Diameter: 5/16"
Diameter 2: 9/16"
Thickness: 3/4"
Material: Stainless Steel
Finish: Polished
Driver Type: 1/2" Wrench
Thread Size: 18 (Coarse)
Shape: High Crown Acorn
Hardness: 18-8
Type: Cap Nut

Box of 6.

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