100% FOOD GRADE SOFT SILICONE - Safe, BPA-free,FDA Approved, odorless, Non-toxic, NO Deformation, Heat-Resistant, Harmless, Tasteless.They are heat & frost resistant from 464F/240C to -104F/-40C. SET OF FIVE LID COVERS - Lid sizes fit most food containers such as cups, mugs, plates, pots, bowls (30CM/11.8, 25CM/9.8, 20CM/7.9 15CM/5.9, 10CM/4). HYGIENIC FOOD COVER - Shields food from dust, insects, and dirt especially when having a picnic or outdoor barbecue. Great for daily use and parties. Retains food freshness and best for storing leftovers and as an oil splatter cover. HOW IT WORKS - The way vacuum lids work is you gently press in the middle and the lid creates airtight, watertight and spill-proof seal. You can then use them to store leftovers, foods, salads, vegetables, pasta, soups, ingredients etc. They are also great for cooking, steaming, simmering, re-heating, keeping meals warm for longer, preserving foods in the fridge or freezer etc. To remove the lid: just peel it off using the little flap on the edge or lift it up from the side.