18"

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.

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

Large wood screws technically called lag screws.

Fasteners for anchoring in stone, concrete, brick and drywall, etc.

Bolts or screws with a circular ring on the head.