Foam latex or latex foam rubber is a lightweight form of latex containing bubbles known as cells, created from liquid latex. The foam is generally created though the Dunlop or Talalay process in which a liquid latex is foamed and then cured in a mold to extract the foam. Structural enhancements are applied to a foam by making different choices of polymers used for the foam or through the use of fillers in the foam. Historically, natural rubber latex is used for the foam, but a similar commercial contender is styrene-butadiene latex, which is especially designed for use in latex foams. Mineral fillers may also be used for the enhancement of properties like stability, load bearing, or flame resistance, but these fillers often come at the cost of lowered tensile strength and extension at break, which are generally desirable properties in the product. Latex foam has properties of energy absorption, thermal conductivity, and compression that make them suitable for many commercial applications like upholstery, soundproofing, thermal insulation (especially in construction), and transportation of goods. Foam latex is also used in masks and facial prosthetics to change a person's outward appearance. The Wizard of Oz was one of the first films to make extensive use of foam latex prosthetics in the 1930s. Since then, it has been a staple of film, television, and stage productions, in addition to use in a number of other fields. Single use plastics and polymer foams are often disposed of in landfills, and there is a growing concern about the amount of space this waste takes up. In an effort to make the foams more environmentally friendly, research is being done into fillers than can achieve the same enhancements as mineral while also increasing biodegradability of the product. Examples of such fillers include eggshell powders and rice husk powders. Structure Latex foam is a form of latex that is lightweight and expanded. Cellular air bubbles are created inside liquid latex, and they can be shaped into different shapes and sizes. The extension of the foam is defined by the amount of air inside of these cells. Lower density and more extended foams tend to have cells which are more polyhedral, while less extended foams tend to have more spherical cells. While the density of the foam () can be measured, a more important property is relative density of the foam to the density of the original