1. Prevents Rain, Snow, and Animals from entering the Chimney Flue.

2. Will keep out 80% of rainfall per year. (Approximately 29" in NE Indiana)

3. Rain will cause rusting of damper and metal parts.

4. Rain will mix with creosote and turn into Highly corrosive acid and create a nasty smell.

5. Stops leaves from entering the flue which act as a breeding ground for insects.

6. Stops heavy down draft from entering flue.

7. Help keep sparks from landing on roof.

8. Lifetime warranty by the Manufacturer!!!