Product name: SK Fresh-Keeping Seal Bag - M (20 Pcs) Specifications: 18cm*20cm+3cm*20 pieces Material: PE polyethylene (ethylene homopolymer) Heat-resistant temperature: -20°C~100°C Shelf life: 5 years Production date: see packaging Product grade: qualified product Tight and leak-proof Intimate labels Food contact acceptable Can be refrigerated or frozen