In order to buy the correct vent repair device, you must determine what size vent shield you need.  You may do this by measuring the diameter of your vent at the exit. If it’s 3 inches or under including flashing, then you need a Small (S) Vent Repair Flashing. If its 4 inches in diameter including flashing you need a Large(L) Vent Repair Flashing. You may notice that the lead flashing is very rough (not round) and beat up on top, this is because it is a sheet of lead that is folded over the pipe and some home builders are less careful than others. However, this lead flashing layer is very soft and can be tapped with any small hammer, wrench, screwdriver, or by hand into a round shape that will fit under your new Critter Quitter®. Below is a video showing you how to measure the vents.

Select one of the 2 links (based on vent size) to get your new Critter Quitter directly from

Determining Diameter


Homes built prior to 1960 often had large cast iron 4 inch vents. These will have a 5 3/8 inch diameter flashing. If you have one of these, or a newer home with the oddball 4 inch vent, we can supply you one of our Extra Large (XL) shields. Call us at 407-808-2501 for more information on how to order.

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