The Winchester Flush Modified Choke Tube is designed for 20-gauge shotguns, featuring a constriction of .600. It is compatible with various shotgun brands including Winchester, Mossberg, Browning Invector, Weatherby, and Savage.Key FeaturesInterchangeable Compatibility: Works with a range of shotgun brands for versatility.Knurled End: Allows for easy installation and removal.Marked Constriction: Constriction size is clearly marked on the side for quick reference.