greenhouse window vent opener with double spring automatic

Important Notice: 1. Automatic ventilation of greenhouse can not be used at temperatures above 50 (122 F) 2. Make that your greenhouse window opens normally Specifications: Maximum height of the window opening about 45cm The temperature of complete opening about 30 (depending on adjustment and load) Maximum weight not more than 7kg/15lb, Opening temperature regulated 16 to 25 Note When you receive this item in summer, you need to put the black bar into the refrigerator not less than 5 minutes to make the cylinder retracted fully before you assembly this product. Color: Black & Silver Material: aluminium alloy Package Contents: 1 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 the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.