Description: Ingenious temperature-sensitive automatic vent opener can automatically open and close window frame, really works well in maintaining the greenhouse within the preferred temperature range. The vent opener starts opening between 15-25 celsius (60-77 Fahrenheit ), depending on how you have adjusted the cylinder. Features: [Automatic Vent Opener]Greenhouse windows opener can open and shut your greenhouse window automatically to maintain the best-growing temperature and prevent your greenhouse from overheating. [Wide Applicability]The vent opener can be closed manually and is easy to install, fit for most aluminum frame greenhouses. [Adjustable Temperature Range]Temperature range is adjustable from 15-25 celsius (60-77 Fahrenheit ) by turning the cylinder, maximum opening at about 30 celsius /86 Fahrenheit (depending on adjustment and load). [High-quality Construction]Durable and rust-proof Iron windows opener with paint spraying for last long time use. [15lb Load Bearing]Use the Standard Vent Opener to lift up to 7kg / 15 lbs. Specifications: Material: Aluminum, Stainless Steel Color: Black Star open at::15-25 celsius (60-77 Fahrenheit ) Fully open at: 30 celsius /86 Fahrenheit Max open distance: 45cm/17.71inch Load bearing: 7KG / 15lb Cylinder Length: 33.8cm / 13.3inch Package Size: 37.5*9.8*4.5cm / 14.76*3.85*1.77inch Package Weight: 439g / 0.96lb Package List: 1 * Automatic Vent Opener 1 * Cylinder 1 * Package of Accessory 1 * Manual (English) Note: Do not heat to more than 50 celsius (122 Fahrenheit ). Do not dismantle the cylinder. Do not apply excessive loads by locking or covering window.