Urinal screens, sometimes also called urinal mats or bowl blocks, are small strainers that are placed inside the urinal bowl to keep cigarette butts, gum wrappers, and other debris from entering and clogging the urinal drain. These small mats are usually made of flexible plastic to fit a variety of urinal sizes. Some models have deodorizing and antibacterial features, and others serve as holder for disinfecting urinal blocks or urinal cakes. Most deodorizing features last about 30 days. Any type of urinal screen is an important feature in public restrooms to reduce the risk of clogged urinals.