Prime-Line 9062583 Carriage Bolts, 1/4 In.-20 X 4-1/2 In., A307 Grade A, 50 Pack Carriage bolts feature a slightly rounded head and have no exposed sharp edges when fully fastened. Due to that reason, they are often used when a more aesthetic look is desired. They are commonly used on docks and on playground equipment or in cases where it may be difficult to reach the bolt head with a tool. The square shoulder on carriage bolts help to hold it in place while the nut is fastened. Size: 1/4 inch-20 X 4-1/2 inch Features a smooth rounded head as opposed to a standard hex head Square shoulder allows for nut to be tightened or loosened Often used in cases where a protruding bolt head could cause injury Nuts and washers not included, ensure washers and nuts are same diameter Thread Type: Coarse, Thread Class: UNC-2A, Point Style: Blunt Specification(s) Met: ASME B18.5 and ASTM A307A