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 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. Simply inflate it with the provided pump to install, and deflate to remove. The balloon allows for a little ventilation and is completely reusable. It measures 580x360mm.