A sealer is a substance or product used to create a protective layer over surfaces, preventing moisture, dirt, and other contaminants from penetrating. Sealers are commonly applied to materials like wood, concrete, and stone to enhance durability and longevity. They can be found in various forms, including liquids, sprays, and pastes. In construction and home improvement, sealers play a crucial role in maintaining the integrity of structures. For example, a concrete sealer can protect driveways from water damage, while a wood sealer can prevent rot and decay in outdoor furniture. Proper application of sealers can significantly extend the life of materials.