HIGH QUALITY&DURABLE-Made of high quality of galvanized steel.Durable and strong for long time use. COMPLETE AUTOMATIC-This vent opener will automatically open and close your greenhouse window while the environment temperature changes , which will help you maintain the best growing temperature and prevents your greenhouse from overheating. NON ELECTRIC-Use solar energy only,no batteries or electricity required.Economic and Eco-friendly. TWO SPRINGS&HIGH LIFT CAPABILITY-Lifts vent weight up to 33 lbs (15 kg ),covers most of greenhouse windows.If you it is still not enough for your window,you could use two window openers together. EASY TO INSTALL- Fit for most of aluminum&wooden frame greenhouse. Comes with a fitting accessory pack and a detailed manual for easy installation. Automatic Two Springs Greenhouse&Cold Frame Vent Opener

Specifications:

Material:Durable galvanized steel

Technical Data:

1.Maximum window opening approximately 17.7inch (45cm)
2.Lifts weight up to 33lbs (15kg)
3.Maximum opening at 91.4℉ (33℃ ), depending on adjustment and load.
4.Open temperature adjustable from 60.8℉ to 77℉ (16℃ to 25℃ )

Note:

1.Do not use your window opener where temperature will exceed 140℉ ( 60℃ );
2.Before installation, make ensure your window can be opened without obstacle,otherwise damage might occur.
3.Do not apply excessive loads by locking or covering window.
4.When you receive this item in summer,please put the black part of cylinder(ONLY BLACK PART) into the refrigerator not less than 5 minutes to make the cylinder rod retracted fully before you assemble the vent opener.