Machined brass guide with protective O-Ring retainer prevents damage to rifling and coated cleaning rods. Keeps rod centered; will not scrape coating from rod. Four different sizes fit .30 through .45 caliber barrels; accommodate all .30 caliber coated rods. Mfg: Dewey SPECS: Machined brass. C-30 fits .30-308 caliber. C-35 fits .35-358, 9mm, 357 caliber. C-45 fits .45, 45/70, .458 caliber.