Briley Winchester Win Choke Flush Black Oxide 12 Gauge Modified .020. The WinChoke system allows you to determine the constriction of the choke by changing its position in the barrel. The position of the choke tubes determine the constriction of the bore which in turn determines the amount of energy needed to produce that perfect shot. With more energy being put out by the choke tubes less powder will be expended during the shot therefore less wad required for both short and long-range shotguns. Briley Winchester WinChoke Flush Choke Tubes also perform exceptionally well in reducing recoil improving accuracy and limiting muzzle jump. These advantages make Briley Winchester WinChoke Flush Choke Tubes the most popular for both shooters and hunters alike. Specifications for Briley Winchester WinChoke Flush Choke Tube: Manufacturer: Briley Gauge: 12 Choke Tube System: Winchester Choke Gun Make: Winchester Package Contents: Briley Winchester WinChoke Flush Choke Tube Briley WINFB12M: Winchester Win Choke Flush Black Oxide 12 Gauge Modified .020