The De Vielle Chimney Balloon Medium is an inflatable, reusable balloon that fits snugly into your chimney, preventing heat loss and cold drafts from entering your home. It's easy to install and remove, helping to lower energy bills and keep your living space cozy during colder months. The balloon stops down draughts and updraughts, and prevents debris, soot, and bird mess from entering your home. It can be inflated with the pump provided to install, and deflated to remove. This allows for a little ventilation. The balloon is completely reusable and measures 580x360mm.