TruePower Automatic Vent Opener Standard - Lifts 15 Lbs Solar Vent Opener can lift up to 15 lbs. Automatic window opener opens and closes your greenhouse vent panels Raise or lower the temperature setting with a simple twist of the cylinder and can be adjusted from approximately 65 to 80 degrees Fahrenheit No electrical power is required as the fluid-filled cylinders expand in warm temperatures Screw directly into polycarbonate panels, wood, or metal frames. Put the cylinder in a cool place at max. 50F for at least 30 minutes before the assembly. NOTE: Refer the User Manual before use.