A chimney cap is a protective cover placed on the top of a chimney. Its primary purpose is to prevent rain, snow, and debris from entering the chimney, which can cause damage and blockages. Additionally, a chimney cap helps to keep animals, such as birds and squirrels, from nesting inside the chimney. Chimney caps are typically made from materials like stainless steel, copper, or aluminum. They often feature a mesh screen to allow smoke to escape while keeping out unwanted pests. Proper installation of a chimney cap can enhance the efficiency of a fireplace or wood stove and reduce the risk of chimney fires.