Our "lifetime guaranteed" caps protect against rain, animals, birds, and leaves. They may also help with smoking problems. You need a chimney cap because rain attacks mortar joints causing cracks and brick erosion, weakening the whole structure of your chimney. Although a cap cannot stop all moisture, it will prevent rain from pouring down your chimney year after year and rusting your damper and damper connections, causing greater down draft and increasing your utility bills. And let's not forget our animal friends! They will eventually find your chimney, if they haven't already. A cap can stop birds, squirrels, and raccoons from venturing into your home. Even if they don't come down the chimney, their droppings mixed with the rain and warm weather can set off a foul smell that you won't enjoy.