Exaco RIGA Auto Opener - Automatic Window Opener Exaco RIGA automatic window opener opens and closes your greenhouse vent panels for reliable climate control even when you?re away No electrical power is required as the fluid-filled cylinders expand in warm temperatures Raise or lower the temperature setting with a simple twist of the cylinder and can be adjusted from approximately 65 to 80 degrees Fahrenheit Made of steel with paraffin in the vent opener cylinder Rated to lift up to 15-pounds