www.pmmag.com/articles/88518-gas-venting-from-metal-fab-inc
Gas Venting from Metal-Fab Inc.
July 1, 2005

Metal-Fab Inc. has announced the addition of new 3-, 4- and 5-inch diameters to its line of Corr/Guard® Special Gas Vent for condensing appliances. It is available in single-wall and double-wall designs. The single-wall features special snap-lock tabs that “click” into locked position when the pipe is pushed together - no tools required.
Circle 53