Carriage bolts are round head square neck screws

Generally speaking, bolts are used to connect two objects, usually through light holes, and need to be used in conjunction with nuts (nuts), and a single one does not work for connection. The tool is generally a wrench. The head is mostly hexagonal, generally larger. The carriage bolts are used in the grooves, and the square neck is stuck in the grooves during installation, which can prevent the bolts from rotating, and the carriage bolts can move in parallel in the grooves. Since the head of the carriage bolt is round, there is no design of available power tools such as cross recesses or inner hexagons, which can also play a role in preventing theft during the actual connection process.