1-1/4", Hex, US

US Fasteners

Hex head

Sheet metal screws

Screws with large threads for use in sheet metal sometimes also used in plastic, fiberglass or wood.
Hex bolt

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.
Lag bolt

Lag bolts

Large wood screws technically called lag screws.