Vendor Information: The product is a simple, self contained device that is installed into drainage systems with no tools. The product collapses to fit in pipes draining onto the street and once in place expands to lock into the drain. The simple trap door on the front of the product allows water, debris and other effluent to flow uninhibited out of the drain. When the device is not draining water, the flap prevents pests from entering the drainage system. The advantage of the product is that it effectively covers the drain hole preventing intrusion and has minimal flow restriction.