Well, there are two types of storm doors in the market place today. There is what we call an 'extruded aluminum door,' which is basically a hollow aluminum tube in various shapes that meet at the corners to form a rectangle. Extruded aluminum doors are great constructions. They allow a decorative look to the product. They have long-lasting finishes on the extruded aluminum doors. They are made to last an extremely long time. A lot of these products have almost a lifetime warranty. The other version is a wood core door, which is a solid wood panel with a couple of different surfaces available. A vinyl clad, which refers to that solid wood core with a vinyl skin adhered to it, is very durable. It is resistant to scratching. However, color selections are normally limited in vinyl clad doors. The next selection would be an aluminum clad door. An aluminum clad door would have aluminum skin adhered to the wood core. Normally, this offers a few more color selections. In the wood core series, the main feature is stability. It's very sturdy. It can take a lot of abuse. These storm doors are great for high traffic areas and people with kids or pets. They are perfect for those types of openings. Solid wood doors are not something that you see also. They are available. However, most have some finish or something else on top of them. The finish would prevent problems with warping or twisting. The nice thing about these finishes, the aluminum clad wood core, vinyl clad wood core, or extruded aluminum, is that they are very low maintenance products. There may be some basic cleaning occasionally, but for the most part, they pretty much take care of themselves.