5/16"-18 x 3-1/4" Carriage Bolts with Nuts, Steel, Zinc Plated

Carriage Bolts, also called round head square neck bolts, generally feature a broad, shallow round head and are inserted into pre-drilled holes. The square neck under the head keeps the carriage bolt from turning as the nut is tightened. Carriage bolts are commonly used to fasten wood or wood and metal parts together.