Traditional dampers are located in the "throat" of a fireplace. They are made of cast-iron and are housed in a low-tech framework. These cast-iron dampers do not seal well-they have a leaky, rough, metal-to-metal seal. Recent lab studies have shown that even a new throat damper can leak up to $200 for heating and cooling a year. Imagine how much energy an old, rusted out damper leaks! Lock Tight Energy Saving Dampers seal tightly to save you money. Lock-Tights rubber gasket seals tightly like a storm door for your fireplace and keeps heating and cooling dollars where they should be...in your home. LockTight mounts on top of your chimney to keep out animals and rain, and easily operates from inside your firebox, sealing tight every time you close it-eliminating any draft. Stainless Steel is the most popular cap material due to its longevity and flexibility of fuel being burned.