When It Rains, It Drains.™ When It Shines, It Rewinds.™ The RAINDRAIN™ rain removal system is that simple in operation. The force of the rain traveling to the downspout will start the RAINDRAIN™ water extension process through the perforated holes. It rains and it will automatically unroll, the rain stops and it will automatically rewind. Simple process, vital protection. Exclusively designed and engineered with a built-in flush system. Simply slide the grooved plastic fastener off from the end of the RAINDRAIN™ to flush and release any debris to flow through.