So Clean, So Simple, So Wise. The Palram 6\' x 4\' Harmony Silver Polycarbonate Greenhouse merges a smart and clean design with a beautiful, functional and sturdy structure to create a simple assembly and improved use. Harmony greenhouses are maintenance free, comprised of rust resistance Aluminum frame and crystal clear, virtually unbreakable glass-like Polycarbonate panels, which provide extra durability for many seasons to come. It is a perfectly nourishing environment for your precious flowers and plants.