Glass is pre-heated oven-safe up to 425°F. Our Anchor Hocking 13294L20 10-Piece Round Food Storage Set are also microwave, freezer, and dishwasher safe, and are up to 100% stronger than regular glass. Truly sealed glass food storage containers help protect the flavor of food and will not stain or absorb odor - they are also stackable and nestable for easy storage. True seal lids are designed to prevent spills and leaks and lock air out while sealing freshness in.