Question: Styrophone is often made from what type of closed-cell polystyrene?

full_context: Document 1: Dow Chemical Company: The Dow Chemical Company, commonly referred to as Dow, was an American multinational chemical corporation headquartered in Midland, Michigan, United States, and the predecessor of the merged company DowDuPont. In 2007, it was the second-largest chemical manufacturer in the world by revenue (after BASF) and as of February 2009, the third-largest chemical company in the world by market capitalization (after BASF and DuPont). It ranked second in the world by chemical production in 2014.
Document 2: Dichlorodifluoromethane: Dichlorodifluoromethane (R-12) is a colorless gas usually sold under the brand name Freon-12, and a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in developed countries (non-article 5 countries) in 1996, and developing countries (article 5 countries) in 2010 due to concerns about its damaging impact to the ozone layer. Its only allowed usage is as fire retardant in submarines and aircraft. It is soluble in many organic solvents. Dichlorodifluoromethane was one of the original propellants for Silly String. R-12 cylinders are colored white.
Document 3: Gramophone record: A gramophone record (phonograph record in the US), commonly known as a vinyl record or simply vinyl or record, is an analog sound storage medium in the form of a flat polyvinyl chloride (previously shellac) disc with an inscribed, modulated spiral groove. The groove usually starts near the periphery and ends near the center of the disc.
Document 4: Foam weapon: A foam weapon, (also known as a boffer, padded weapon, or latex weapon), is a padded mock weapon used for simulated handheld combat. Such weapons are used in simulated battles called battle gaming and in some live action role-playing games (LARPs).
Document 5: Bubble Wrap (brand): Bubble Wrap (originally Air Cap) is a trademarked brand of Sealed Air Corporation that includes numerous cushioning products made from bubble wrap. The brand is produced by the Product Care division of Sealed Air. Both the Bubble Wrap brand and product were introduced in 1960, with the launch of Sealed Air. Although the brand was originally used for the packaging of IBM computers, Sealed Air now does most of its Bubble Wrap business in the food packaging industry.
Document 6: Cardboard record: A cardboard record was a type of cheaply made phonograph record made of plastic-coated thin paperboard. These discs were usually small, had poor audio quality compared to vinyl or acetate discs, and were often only marginally playable due to their light weight, slick surface, and tendency to warp like a taco shell. Playability could be improved by placing a coin between the lock groove and the spindle hole to add weight and stability. These records are distinct from both flexi discs, which are sturdier, and from many of the old home-recording discs since cardboard discs were mass-produced for a specific purpose.
Document 7: Starlite: Starlite is a material claimed to be able to withstand and insulate from extreme heat. It was invented by amateur chemist and hairdresser Maurice Ward (1933–2011) during the 1970s and 1980s, and received much publicity in 1993 thanks to coverage on the science and technology show "Tomorrow's World". The name Starlite was coined by Ward's granddaughter Kimberly.
Document 8: Styrofoam: Styrofoam is a trademarked brand of closed-cell extruded polystyrene foam currently made for thermal insulation and craft applications. It is owned and manufactured by The Dow Chemical Company.
Document 9: Hot-wire foam cutter: A hot-wire foam cutter is a tool used to cut polystyrene foam and similar materials. The device consists of a thin, taut metal wire, often made of nichrome or stainless steel, or a thicker wire preformed into a desired shape, which is heated via electrical resistance to approximately 200°C. As the wire is passed through the material to be cut, the heat from the wire vaporises the material just in advance of contact.
Document 10: Newell Brands: Newell Brands is an American worldwide marketer of consumer and commercial products with a portfolio of brands including Rubbermaid food storage, home organization and reusable container products; Contigo and Bubba water bottles; Coleman outdoor products; Diamond matches; Sharpie, Expo Markers, PaperMate, Dymo, Elmer's, Krazy Glue, Mr. Sketch, Parker Pens, Uniball, Prismacolor, Rotring, Xacto, Waterman, Berol stationery products; Bicycle and Bee Playing Cards; Aprica, Nuk, Tigex, Babysun, Baby Jogger and Graco children's products; First Alert alarm systems; Calphalon cookware and kitchen electrics; Sunbeam, Rival, Crock-Pot, Holmes, FoodSaver, Oster, Osterizer, Mr. Coffee small kitchen appliances; Yankee Candle candles; and Goody hair care accessories.
Document 11: Styrophone: A styrophone is an acoustic device made from expanded polystyrene foam (often referred to by the genericized trademark "Styrofoam") and it goes toot toot. There are at least two varieties:
Document 12: Spokestoon: A spokestoon is an established cartoon character who is hired to endorse a product. It should not be equated with a cartoon character invented specifically to give identity to a product, such as the Michelin Man, Speedy Alka-Seltzer or the Pillsbury Doughboy. For these and more, see List of advertising characters.
Document 13: Dow Corning: Dow Corning is an American multinational corporation headquartered in Midland, Michigan, United States. Originally established as a joint venture between the Dow Chemical Company and Corning Incorporated, it is now owned by DowDuPont and specializes in silicone and silicon-based technology, and is the largest silicone product producer in the world.
Document 14: Stabule: Stabule (stebule, stabuļa) is a national woodwind musical instrument of Latvia. The name can apply to variety of wind instruments, but in general sense it is a pipe with 4-8 finger holes. These instruments are 1.5-2.5 cm in diameter and can be anywhere from 20 to 40 cm in length. Stabules have either fipple or reed. Reed stabules were usually made from wood or reed with mouthpiece also made either from reed or wood. Fipple stabules were usually made of wood, although in some areas clay and bark stabules of this type were made and bone stabules have been found by archaeologists. A similar more simple type of stabule without finger holes can be made from willow bark. This type of instrument differs in that its end (opposite to mouthpiece) is plugged. The plug is generally meant for tuning the stabule, but sometimes also used as a slide to adjust tone while playing. All bark stabules were usually made in spring when bark is looser - the features of the stabule are carved right on a fresh broom of willow and the bark is then slid off; the remaining branch is then used to make the fipple and, for the simpler type of stabules, the plug. Due to the natural shrinkage of bark they were short-lived.
Document 15: Sealed Air: Sealed Air Corporation is a packaging company known for its brands: Cryovac food packaging, Bubble Wrap cushioning, and Diversey cleaning and hygiene. Sealed Air Corporation has three divisions: Food Care, Product Care, and Diversey Care. Jerome Peribere is the CEO of the Charlotte, North Carolina-headquartered Sealed Air.
ground_truth: Styrofoam