The City Greenhouse has been designed for the keen gardener with a small garden or even a balcony but its small size doesn't mean that it comprises on features. Available in two finishes: Aluminium or Anthracite. (PLEASE NOTE: Image for illustration purpose only.) Optional Vent - New louvre vent for value range growhouses and lean-to models. Fits to L/H side of frame. The most useful accessory you can buy for your Value Mini greenhouse or Growhouse. Designed to automatically open as the temperature rises above 18°C (65°F) and then close again as the temperature cools. The unit is ideal if you are out for the day and the weather changes. It is also very useful for models that catch the early sun, as sunrise can be 5:30am in the Summer. Grease filled opener requires no electricity to operate. THESE CAN BE FITTED RETROSPECTIVELY - you will need to drill a 4mm hole in the end plate of your existing frame.