Carriage Bolts Hot Dipped Galvanized Grade 2 W/ Nuts 3/8-16 x 3'' Qty 2500. A carriage bolt, coach bolt or round head square neck bolt is used through iron strengthening plates on either side of a wooden beam. It is commonplace though to use them on bare timber, the squared section giving enough grip to prevent rotation. Carriage bolts are extensively used in security fixings where the bolt must only be removable from one side. The smooth domed head and square neck below prevent the carriage bolt from being unlocked from the insecure side.If the Fastener's length is Less Than 6, The fastener is Fully Threaded. If the Fastener's length is Greater Than 6", The fastener is Threaded 6". Quantity of Fasteners in Package : 2500. Material : Hot-Dipped Galvanized Grade 2 Steel? Tracking is provided on ALL Orders. UPS Next Day Air is available, Please inquire for pricing. For YOU, we constantly strive to find ways to improve our performance.