Unique and innovative, Glasslock's tempered glass is stain resistant and durable as well as healthier and safer for your family. Lids lock with green silicone seal making these airtight and watertight, keeping the foods and flavors locked inside. Microwave safe, non-toxic, and non-reactive, storage unit's seal ensures nothing transfers into your food while reheating. You can take it from the freezer to the microwave with no concern. Environmentally friendly plastic lid and silicone seal. Set includes one 17-oz. square, one 41-oz. square and one 88-oz. square. Not suitable for oven or direct heating. Remove lid before using microwave or reheating. One-year warranty. Top-rack dishwasher safe.