SELKIRK 104325 GAS VENT DOUBLE WALL INCREASER, TYPE B,

SELKIRK 104325 - GAS VENT DOUBLE WALL INCREASER, TYPE B, 4 TO 5-IN. - 4" X 5", 4RV-15DW, GAS VENT DOUBLE WALL INCREASER. ROUND GAS VENT DOUBLE WALL CONSTRUTION WITH IT'S BUILT-IN AIR SPACE, PROVIDES PERMANENT INSULATION AND KEEPS THE INNER PIPE HOT AND OUTER RELATIVELY COOL DOUBLE WALL INCREASER FOR 4 INCH TO 5 INCH APPLICATIONS. SNAP TOGETHER NON-POSITIONAL LOCK SYSTEM UNDERWRITERS LABOTORIES UL 441 AND NATIONAL FIRE PROTECTION AGENCY NFPA 54 AND NFPA 211 VENTING GAS FIRED APPLIANCES, WATER HEATERS, FURNACES, STOVES, ETC. LOCKTAB-AN ALTERNATIVE METHOD TO SECURE PIPE WHEEN REQUIRED BY LOCAL CODE. OUTER MATERIAL 28 GAUGE GALVINIZED STEEL INNER LINER IS ALUMINUM C - EQUAL TO 671253