The ventilated mesh plastic cover ties for the frame and gives best air circulation. A zippered roll-up door gives easy access. Frames like these may be purchased at a local drug or supermarket, at an art retailer, at a camera shop, or on the web from a variety of sources. https://plant-inn-mini-greenhouse94815.therainblog.com/31495284/the-definitive-guide-to-mini-greenhouse-in-stock