These precision rifled choke tubes by Carlson are made from high-strength 304 stainless steel. Each choke tube extends from 0.625 to 1.3 inches beyond the end of the barrel depending on the type of firearm for which the choke tube was specifically designed. Each choke tube has a right-hand shotgun twist, which is 1 in 35. These choke tubes have a matte black finish. If you're looking for improved accuracy from a smoothbore barrel, these fine choke tubes will enhance your groups.