These are .020" Black Styrene Sheets by Evergreen Scale Models.
FEATURES: UV resistant polystyrene. Ideal for scratchbuilding...can be combined with wood, metal, and other plastics. Nontoxic and impervious to many chemicals, including water. Basic cutting, cementing, painting, weathering and wood grain techniques provided on package. Scale converstion chart provided on package. Made in the USA.
INCLUDES: (3) Sheets
TOOLS NEEDED: Stainless-Steel Scale Rule
Self-Healing Cutting Mat
SPECS: Sheet Size: 6" x 12" Thickness: .020" (152mm x 305mm) (0.5mm)