Size: 3/8 inch-16 X 10 inchFeatures a smooth rounded head as opposed to a standard hex headSquare shoulder allows for nut to be tightened or loosened Often used in cases where a protruding bolt head could cause injuryNuts and washers not included, ensure washers and nuts are same diameterThread Type: Coarse, Thread Class: UNC-2A, Point Style: BluntSpecification(s) Met: ASME B18. Carriage Bolts 3/8in-16 X 10in A307 Grade A Zinc Plated Steel 10PK Carriage bolts feature a slightly rounded head and have no exposed sharp edges when fully fastened.. The square shoulder on carriage bolts help to hold it in place while the nut is fastened.