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 rain drain water extension process through the perforated holes. As it continues to rain the gutter drain will automatically unroll, and when the rain stops then gutter drain will automatically rewind. Simple process, vital protection. Exclusively designed and engineered with a built-in flush system.