Ziploc is a bran of disposable, re-sealable zipper storage bags and containers originally developed by Dow Chemical Company, and now produced by S. C. Johnson & Son. According to Dow's website, the bags were originally test marketed in 1968. The bags and containers come in different sizes for use with different products. The brand offers sandwich bags, snack bags and other bags for various purposes. For example, one-gallon, two-gallon, and quart size bags are offered, as well as freezer bags and very large bags for storage. The enormous Ziploc "Big Bag" comes in two sizes: XL (2ft x 1.7ft) and XXL (2ft x 2.7ft). Ziploc storage and freezer bags are made from polyethylene plastic resin.