Automatic Window opener for CARO & DORIS cold frames

The automatic window opener from quality brand GFP provides optimal ventilation for your cold frame by responding automatically to temperature changes, helping to prevent heat build-up and overheating. This is made possible by a clever mechanism: at temperatures of approximately 22 °C and above, a special oil inside the opening cylinder expands, automatically pushing the window open. This allows excess heat to escape – without electricity or manual ventilation. Ideal for when you're away from home or forget to open the window.