5". Product Dimensions: 11" W x 11" H x 11" D. 2" clearance to combustibles. 11" square ceiling support box with 5" diameter. There's no need for locking bands or mechanical fasteners. For an extra margin of safety, the inner wall is 25% thicker than competing chimneys. Designed for normal continuous operation at flue gas temperatures of 1000 degrees Fahrenheit. For use with wood stoves, fireplaces, furnaces, boilers, ranges, water heaters, and other wood, coal, or gas-fueled appliances. A vent pipe with a 5" inner diameter is required for this unit. Where are you having trouble connecting your plumbing infrastructure in your home? Is your project nearing completion? Maybe right where the chimney joins the house? Don't be concerned any longer! Your problem will be solved with our DuraVent Square Ceiling Support Box! With a built-in twist lock mechanism, this product ensures a secure connection between the support box and the chimney pipe. And with inner walls that are 25% thicker than the competition, you can rest easy knowing that your home is safe. So, what are you waiting for? Make a move right now!

Size: 5 Inch Product Dimensions: 11" W x 11" H x 11" D 2" clearance to combustibles 11" square ceiling support box with 5" diameter No locking bands or mechanical fasteners required Inner wall is 25% thicker than competitive chimneys for an extra margin of safety Designed for normal continuous operation at 1000 degree Fahrenheit flue gas temperatures For use with wood stoves fireplaces furnaces boilers ranges water heaters or other appliances fueled by wood oil coal or gas