â¢Size: 1/4 inch-20 X 5 inchâ¢Features a smooth rounded head as opposed to a standard hex headâ¢Square shoulder allows for nut to be tightened or loosenedâ¢Often used in cases where a protruding bolt head could cause injuryâ¢Nuts and washers not included, ensure washers and nuts are same diameter 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.