Replacement, top mount chimney dampers are operated from inside the fireplace. You never have to go outside or on the roof.
Simple for anyone to operated. In fact, they are much easier to operate than an old fashioned throat mounted damper.

Chimney top mount dampers protect the flue pipe from being destroyed over time by Sun, Rain, Freezing and Thawing, etc.

This spring loaded stye keeps a rain barrier in place even when it's open.

For Masonry/Brick Chimneys.
Not only does the chimney top style damper keep your heating and cooling in, it keeps out Squirrels, Racoons, Birds, and many other creatures.
You would not believe what we have found in chimneys.

Top mounted chimney dampers are by far the most cost efficient style of damper. 
They seal nearly 100% of energy in. 
Old throat mounted dampers are very leaky and very hard to operate.
Instead of damper repairs, you'll be better of with a replacement damper.