Fdit -- Window Opener Cylinder Features This is a replacement cylinder for automatic window opener.High sensitive, automatic respond to weather changes, so you don't need to stay near the greenhouse.Non electric, uses solar energy, open or close the greenhouse vents as temperature rises or drops.Great for most greenhouse to open or close window automatically.Time and labor saving, also can supply a better temperature condition of plant's growth. Package Included: 1 x Window Opener Cylinder Only Specifications Material: ABS Color: Black Temperature Range: 20-25℃ / 68-77℉ Size: Approx. 33 x 1.5cm / 12.99 x 0.59in Weight: Approx. 117g Maximum Opening Distance: Approx. 45 cm / 18in Adjustable Length: Approx. 33-45cm/ 13-18in Application: For Under 14 Kg Window Note 1. Please allow 0-2cm error due to manual measurement. Thanks for your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard. 3. No battery or electricity required, need to be refrigerated before use.