Reliable, quality built anodised aluminium automatic window opener for greenhouses. Clamps onto most aluminium greenhouse vents no need for drilling. Can also be used for timber framed vents. Will fit a window weighing 12.5kg, exerting a load of 6.5kg. It is temperature adjustable and can be set to start opening the window from 13-18C. Size: 30 x 6 x 4.5cm.