Sturdy, lightweight foam trays. Can be used in blast freezer, refrigerator, for a heated display or at room temperature. Rigid construction stands up to rugged handling. Designed for in-store use for hand wrapping or wrapping on low tension machines. #7S Supermarket Tray. Food Container Type: Tray; Material(s): Polystyrene; Material Type: Foam; Color(s): Black.