Q: Will the Large DraftStopper fit my masonry fireplace? A: Yes. The Large DraftStopper dimensions are 38" x 16" inflated. Our company researched the sizes of manufactured dampers and designed the DraftStopper to fit 99.5% of masonry fireplaces.  Please check your firebox just below the damper to ensure your firebox is not larger than these measurements.  If the opening is smaller, the Large DraftStopper is designed to curl down on the sides to provide a good seal. FOR RECTANGULAR DAMPERS. Q: Will the Small DraftStopper fit my metal or zero clearance fireplace? A: Yes. The Small DraftStopper dimensions are approximately 18" diameter inflated. Our company researched the sizes of manufactured metal and zero-clearnace fireplaces and designed the DraftStopper to fit 99.5% of zero-clearance fireplaces.  Please check your firebox just below the damper to ensure your firebox is not larger than these measurements.  If the opening is smaller, the Small DraftStopper is designed to curl down on the sides to provide a good seal. FOR ROUND DAMPERS. Q: What is the difference between an insert and a zero clearance fireplace? A: An insert is designed to be placed into an existing masonry or factory built fireplace. A fireplace is either masonry (not zero clearance) or a metal, factory built (zero clearance) unit built for burning wood or gas. Q: What is a zero clearance fireplace? A: A zero clearance fireplace is a factory-built, metal fireplace that is constructed so that it can be placed, safely, close to combustible material. Q: My damper handle stops me from placing the DraftStopper in my firebox, what should I do? A: To accommodate damper handles we designed the large DraftStopper with five oval shaped areas where you can safely make a small slit for the handle to pass through. The Small DraftStopper has a single slit from the outer edge to the center to accomodate a damper handle. Q: Is the product difficult to install? A: The DraftStopper is very easy to install.  Simply follow the enclosed instructions.  Insert a few breathes of air, position the DraftStopper in the firebox just below the damper using the telescoping tee device for support.  Inflate manually with long tube until the opening is sealed. There is no need to over inflate.  To remove, simply release some air, and place the DraftStopper in the storage bag that comes with the kit until you are ready to reinstall.  Always allow your chimney and firebox to completely cool before reinstalling the DraftStopper. Q: I'm not sure which way to insert the DraftStopper in the firebox, is there a difference? A: The Large DraftStopper is a trapezoid shape to mirror the shape of your masonry firebox.   After installation the longer edge of the pillow should be closest to the fireplace opening. The Small DraftStopper is a round shape to mirror the shape of your round damper in your metal, zero-clearance firebox.   Q: Since the DraftStopper is an inflatable device, does it puncture easily? A: The DraftStopper is very strong, it is made from 14ml polyurethane material that was extensively tested to ensure maximum strength & flexibility.  Under normal circumstances, despite the fact it is housed in a rough masonry environment, it will not puncture.  If, however, the DraftStopper is forced against a sharp or jagged object it will puncture. Please check the interior of your firebox prior to installation, if sharp edges are present use a file or other tool to blunt or minimize the sharpness.  If you should puncture your DraftStopper a patch can be cut from the outside edge, glue patch with PVC cement from most building supply stores. Q: Can I return the DraftStopper if I change my mind? A: Due to the harsh nature of the firebox interior, we do not accept returns if opened  except in case of a manufacturing defect.