5/16"-18 x 4-1/2", Zinc plated steel, US

US Fasteners, 5/16"-18 x 4-1/2", Zinc plated steel
Hex bolts Bolts with hexagonal heads and machine threads for use with a nut or in a tapped hole. Also known as hex cap screws or machine bolts.	Machine screws Screws with machine threads for use with a nut or in a tapped hole.
Carriage bolts & Plow bolts Bolts with no drive and machine threads for use with a nut.	Eye bolts & Screw eyes Bolts or screws with a circular ring on the head.