Carlson's, Choke tubes for Remington shotguns. Available 12 ga.in chokes; Cylinder, Full , Improved Cylinder , Improved Modified , Modified, Skeet, Turkey, Extra Full, Extra Turkey. Manufactured from 17-4 heat treated stainless steel. These chokes may be used with lead shot on any constrictions. Steel shot larger than #BB should not be used in any choke tighter than full.