What kind of Kit do I need?
If you are installing a fireplace insert then you need our Insert Kit which in most cases will be a 6 inch diameter kit.
If you are installing a liner for a furnace, boiler, or free standing stove then you need our Tee Kit. Most of the time this calls for a 6 inch diameter kit.
Note: If you are installing the liner in an 8×8 flue make sure you have enough room for the liner. Remember, for Flex King & Flex King Pro the OD is 1/4 inch greater than the ID. For Flex King HD the OD is 3/16 inch more than the ID. If you insulate that will increase the OD by either 1/2 inch or 1 inch depending on the insulation thickness you choose.