Food-grade silicone material ensures safe storage for fruits, veggies, and lunches. Temperature ratings from -4°F to 428°F -20°C to 220°C make them suitable for microwave, freezer, and dishwasher use. Four sizes 350ml, 550ml, 850ml, and 1200ml provide versatile storage options for RV, refrigerator, and kitchen. Collapsible design saves space in travel trailer and kitchen, perfect for travel, camping, hiking, and school or office lunches. Each set includes four collapsible containers with lids for daily storage needs.