Automatic Vent Opener for the Palram Greenhouses (HG1005)
Automatic Vent Opener for Greenhouses and Coldframes
Amazon.com: G-More Greenhouse Automatic Window Opener Automatic Vent Opener with Double Spring Solar Vent Roof Opener Replacement Cylinder Temperature Control, with Solar Power Sensor (Window Vent Opener) : Patio, Lawn & Garden