The barrel bridgeBarrel Bridge The barrel bridge holds the barrel and protects it. It serves as a support for the barrel and helps to keep it in its proper alignment with the other parts of the movement. [Learn More] holds the barrelBarrel The barrel is a cylindrical container that holds the mainspring. The barrel is connected to the winding mechanism. The winding mechanism rotates the barrel, which in turn winds the mainspring. [Learn More] and protects it. It serves as a support for the barrel and helps to keep it in its proper alignment with the other parts of the movement.