We have a range of polystyrene discs / circles available. These range in diameter form 50 mm ( approx 2 inches / 5 cm ) to 380 mm (38cm / approx 15 inches ) , and you can select thicknesses from 12mm ( approx 1/2 inch ) to 150 mm. ( approx 6 inches ).
These discs are all produced from expanded polystyrene containing a flame retarding additive. This if a firm, rigid, white expanded plastic.