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

Context articles: Chowder
BioTek
Crate
Strained yogurt
Hot-wire foam cutter
Whip antenna
Styrophone
Gruel
Styrofoam
Conchylia cup

Chowder is a type of soup or stew often prepared with milk or cream and thickened with broken crackers, crushed ship biscuit, or a roux.
 Variations of chowder can be seafood or vegetable.
 Crackers such as oyster crackers or saltines may accompany chowders as a side item, and cracker pieces may be dropped atop the dish.
 New England clam chowder is typically made with chopped clams and diced potatoes, in a mixed cream and milk base, often with a small amount of butter.
 Other common chowders include seafood chowder, which includes fish, clams, and many other types of shellfish; corn chowder, which uses corn instead of clams; a wide variety of fish chowders; and potato chowder, which is often made with cheese.
 Fish chowder, corn chowder, and clam chowder are especially popular in the North American regions of New England and Atlantic Canada.
BioTek Instruments, Inc. is a privately held Vermont–based manufacturer notable for microplate instrumentation and bio-analytics software for life science.
 It designs, builds, and sells imaging, detection, washing, liquid dispensing and automation products that are compatible with various microplate formats and other sample vessels.
 Microplates, sometimes referred to as Microtiter (microtitre) plates, are typically found in flat or round bottom configurations with multiple wells arranged in a rectangular matrix often made of polystyrene or polypropylene.
A crate is a large shipping container, often made of wood, typically used to transport or store large, heavy items.
 Steel and aluminium crates are also used.
 Specialized crates were designed for specific products, and were often made to be reusable, such as the "bottle crates" for milk and soft drinks.
Strained yogurt, Greek yogurt, yogurt cheese, or labneh (Arabic: لبنة‎ ‎ "labnah"), is yogurt that has been strained to remove its whey, resulting in a thicker consistency than unstrained yogurt, while preserving yogurt's distinctive, sour taste.
 Like many types of yogurt, strained yogurt is often made from milk that has been enriched by boiling off some of its water content, or by adding extra butterfat and powdered milk.
 In Europe and North America, it is often made with low-fat or fat-free yogurt.
 In Iceland a similar product named skyr is produced.
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.
A whip antenna is an antenna consisting of a straight flexible wire or rod.
 The bottom end of the whip is connected to the radio receiver or transmitter.
 The antenna is designed to be flexible so that it does not break easily, and the name is derived from the whip-like motion that it exhibits when disturbed.
 Whip antennas for portable radios are often made of a series of interlocking telescoping metal tubes, so they can be retracted when not in use.
 Longer ones, made for mounting on vehicles and structures, are made of a flexible fiberglass rod around a wire core and can be up to 35 ft (10 m) long.
 The length of the whip antenna is determined by the wavelength of the radio waves it is used with.
 The most common type is the "quarter-wave whip", which is approximately one-quarter of a wavelength long.
 Whips are the most common type of monopole antenna, and are used in the HF, VHF and UHF radio bands.
 They are widely used as the antennas for hand-held radios, cordless phones, walkie-talkies, FM radios, boom boxes, and Wi-Fi enabled devices, and are attached to vehicles as the antennas for car radios and two-way radios for wheeled vehicles and for aircraft.
 Larger versions mounted on roofs and radio masts are used as base station antennas for police, fire, ambulance, taxi, and other vehicle dispatchers.
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:
Gruel is a type of food consisting of some type of cereal—oat, wheat or rye flour, or rice—boiled in water or milk.
 It is a thinner version of porridge that may be more often drunk than eaten and may not need to be cooked.
 Historically, gruel has been a staple of the Western diet, especially for peasants. Gruel is often made from millet, hemp, barley or, in hard times, from chestnut flour or even the less bitter acorns of some oaks.
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.
A conchylia cup is a Roman cup type with a conical base and a slightly everted rim, made of transparent to slightly colored glass.
 Its distinguishing characteristics are stylized open mouthed fish with indented fins and curving tails, often made of translucent glass and applied wavy colored threads, and affixed to the outer surface of the cup to produce its three-dimensional aspect.
 The most common type appears to have stylized fish swimming to the left.
 These vases could be entirely free-blown or their cup shape mold-blown, and the fish, or other sea creatures, free-blown onto it.
 The only four intact conchylia cups were found in Cologne, Trier, and Rome.
 Both Cologne and Trier have been suggested as manufacturing centers.
 Fish appliqués have been found throughout the Mediterranean, and provide no good clues for provenance.
 These cups were possibly used either as oil lamps, drinking vessels or for holding garum sauce.
 The most current thinking is that they were oil lamps, based on stylistic comparison with a 'cage' cup from Szekszard, Hungary, but may not be an entirely satisfactory answer, given that there seems to be no practical way of placing a wick in the cup.
 The only cup stemming from a datable context is from Cologne, and dated to the fourth century A.D.
 It is preserved in the Römisch-Germanisches Museum, Cologne.