The Undertaker XT High Density Ported Choke Tube works with High Density Hevi-Shot bismuth and tungsten loads in 12 and 20-guage shotguns. Features blued finish 3-inch long tube. Knurled end for easy hand installation. Fits all 2-3/4 3 and 3-1/2 guns. - Winchester Mossberg Browning Invector Charles Daly O/U Ithaca H & R Thompson Center - 20 gauge