Specification:Condition: Item Type: Window Opener Material: Aluminium Opening Force: 25kg / 55lb Operation Area: Start at 17-25℃ (63-78℉) Maximum Open: Full at 30-32℃ (86-90℉) Closing Force: 15kg / 33lb via heavy duty spring Support Bar Length: Approx. 34cm / 13.4in Spring Fixing Tool Size: Approx. 14 x 5 cm / 5.5 x 2 in Weight: Approx. 343g / 12.1oz Package List:1 x Support Bar1 x Spring Fixing Tool4 x Slotted Screw2 x Small Cross Nail4 x TD Screws2 x Small Screw4 x Large Round Fixed Ring2 x Small Round Fixed Ring2 x Round Iron Ring1 x Instruction Manual Features Durable in use:Made of high quality aluminium material, not easy to rust and durable in use. Safe and reliable:Spring and support bar provide additional protection against wind damage. Temperature changes:The window opener automatically opens and closes as the temperature changes. Universal: easy to install and use, suitable for any blind window, easy to use. Electricity required:Easy fitting by clamps or screws provided, no batteries or electricity required.