Tupperware is the brand name of a series of plastic food storage products for the home. Tupperware is designed to keep food flavor and odor inside the container. The design of products goes through a rigorous approval process resulting in a prototype which is used for engineering specifications. Metal molds are then designed, constructed and shipped to the various Tupperware manufacturing plants around the world. Tupperware is dependent on the petroleum industry, as plastics are a byproduct of the petroleum industry. Synthetic plastics came into being during WWII with the shortage of natural resources. Although the plastics used go through their own quality control upon purchase, they too undergo quality control tests by Tupperware. The combination of plastics are chosen for their meltability, weight and specific gravity. The molding machines are overseen by both an operator and a preventative maintenance team. The final products go through quality control tests to ensure proper seal, weight and stress. The packaged and boxed finished products are transported by truck and/or rail to franchise distributors. Franchised dealers sell and distribute Tupperware through the home party plan. The dealers themselves get together at conventions - the one in the US called Jubilee - both to discuss marketing and sales opportunities as well as have some fun, Tupperware style.