This is a set of models that when 3d printed creates famous bounty hunter Samus Aran's Omega Arm Cannon from Metroid Dread. This version is able to open and close the barrel shroud while also retracting the barrel to activate Charge Shot mode by using a series of 4 bar mechanisms. You will need some bolts (1/4 inch and 5mm), nuts, and 4 springs (23/32-Inch by 3-1/2-Inch by .041 Diameter) for the opening action.