Durable foam construction makes hinged lid containers a perfect lunchtime or dinnertime choice. Containers are insulated to maintain food temperatures at their tastiest. Excellent for use with both hot and cold foods. SmartLock® closure keeps food secure. Hinged lid foam containers provide a safe and durable option for taking food on the go. Sandwich. Food Container Type: Hinged Lid Container; Material(s): Polystyrene; Food Container Material Type: Foam; Color(s): White.