Important Notice: 1. Automatic greenhouse ventilation cannot be used at temperatures above 50° (122 F) 2. Ensure your greenhouse window opens normally Specifications: Maximum window opening height about 45cm Full opening temperature about 30° (depending on setting and load) Maximum weight of vents not exceeding 7kg/15lb, regulated opening temperature 16°-25° Note When you receive this item in summer, you need to put the black bar in the refrigerator at least 5 minutes for the cylinder to fully retract before assembling the product. Color: Black and silver Material: Aluminum alloy Package Contents: 4 x Automatic Window Opener Kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in a little different from the real thing. The measurement allowed error is +/- 1-3 cm.