This is a replacement cylinder for automatic window opener. High sensitive, automatic respond to weather changes, so you don't need to stay near the greenhouse.Product description 1. The automatic hole opener is suitable for most of the current garden greenhouses. 2. The greenhouse accessories are easy to install and can be screwed directly into the polycarbonate board, wood or metal frame. 3. The greenhouse automatic window opener can prevent wind gusts and can be clamped on the greenhouse without drilling holes.Features: Non-electricity, using solar energy. save time and energy.Product attribute Material: Plastic + Metal Color: black + silver Type: Window Opener ToolWarm reminder 1. Please remember that due to the lighting effects, the monitor's brightness / contrast settings / etc's, there will be some slight differences in the color of the pictures and the actual items. Measured by hand, deviations of 1-2 cm are possible. 2. Please leave us a message if you have any questions. We will respond and offer you our best service.