Allows you to attach an 8"x8" to 10"x10" item like an 8"x8" Lock-Top Damper (or similar) to top of an 8" diameter (inside flue dimension) round flue. Works on 8" round clay tile masonry flue, 8" round stainless steel liner, 8" solid-pack prefab chimney and 8" modular chimney. 8" diameter end of adapter is slightly less than 8", so it slides into 8" diameter flue easily. Works with most top dampers, except for Lyemance. Made of heavy 304 stainless steel, so should last practically forever. Holds pretty well without caulk or screws, but can be glued in with silicone sealer or stainless steel self-tapping screws. If your Lock-Top Damper comes with a chimney fire Safety Device, it will be too big to use with this adapter. Adapter comes with a smaller Safety Device to fit this adapter and only takes a few minutes to swap out the larger for the smaller device pictured in above photos. Not for use on an Air-Cooled prefab chimney, as may interfere with air-cooling and cause chimney to overheat.
After 43 years, we closed down our chimney sweep business and a year later are selling all our brand new inventory for 50% (or more) off wholesale list prices. We are much cheaper than most others on eBay, as we are not trying to make a profit, but need to clear out our inventory for good at a loss. Once one of our listings is sold out, it is gone for good. We were a service business, so we don't mind answering any technical or aesthetic questions about these products and how they work.