1/4" x 5-1/2"

US Fasteners

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.
Machine screw

Machine screws

Screws with machine threads for use with a nut or in a tapped hole.
Carriage bolt

Carriage bolts & Plow bolts

Bolts with no drive, and machine threads for use with a nut.
Lag bolt

Lag bolts

Large wood screws technically called lag screws.
Socket product

Socket screws

Screws with an allen wrench drive.