A coaster is a small, flat object used to protect surfaces from moisture, heat, or scratches caused by beverages. Typically made from materials like cork, wood, or plastic, coasters are placed under cups, glasses, or mugs to absorb spills and prevent damage to tables or countertops. They come in various shapes, sizes, and designs, making them both functional and decorative. Coasters can also serve as promotional items for businesses, featuring logos or branding. In addition to their practical use, some people collect coasters as a hobby, showcasing unique designs or themes. Coasters are commonly found in homes, restaurants, and bars.