Tupperware, with the lid that "burps," has been a fixture in American kitchens since 1945. The plastic containers, airtight and touted as kitchen timesavers, come in a wide range of sizes, shapes, and uses. Tupperware parties, at which a hostess demonstrated the items for sale and took orders from her friends and neighbors, emerged in 1951 and became as well known as the product itself. Tupperware catalogs of the 1950s encouraged women to host events as a means of earning money in a way that did not require daily office work, a proposal attractive to many stay-at-home moms of the baby boom years. Large sales volumes enabled women to rise in the ranks, learning managerial skills and eventually becoming Tupperware distributors. In addition, meeting sales goals earned sellers Tupperward play sets like this one for their children. Tupperware products have remained reliable tools of the 21st-century kitchen, but the company has changed with the times. In addition to selling its goods through home parties, Tupperware also sells its many products online.