5/16" x 1-3/4", Zinc, External hex

US Fasteners, 5/16" x 1-3/4", Zinc, External hex
Sheet metal screws Screws with large threads for use in sheet metal sometimes also used in plastic, fiberglass or wood.	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.
Flange bolts Flange bolts have a flange on the bottom of the head that distributes the load like a washer.	Lag bolts Large wood screws technically called lag screws.