After installed this temperature controlled automatic vent opener, your window will be a self opening one. It is solar heat sensitive that open the vent when weather warms up and then closing when it cools down. Really works well in maintain the greenhouse within the preferred temperature range. Features: Elongated aluminum cylinder with paint spraying, weather resistant. Solar heat sensitive vent opener, automatic stretch or shrink the vent while the temperature is changing. Stainless steel accessories would last long time use. Aluminum frame looks more lustrous, durable and rust-proof. Easy to install, universal fit for all aluminum frame greenhouse. Auto-opening temperature range is adjustable from 15-25(60-77). Maximum opening at about 30/86(depending on adjustment and load). Suitable for the vents weighting up to 7kg/15lb. Specifications: Material: Aluminum+SS Item Weight: Approx. 305g / 10.78oz Package Weight: Approx. 387g / 13.66oz Package Size: Approx. 38 * 9.5 * 4.5cm / 14.96 * 3.74 * 1.77in Package List: 1 * Vent Opener 1 * Package of Accessory 1 * Manual (English) Note: Do not heat to more than 50(122). Do not dismantle the cylinder. Cooling the cylinder for 24 hours before installation.