Ezi seal lids are 100% food grade silicone. They with stand heat up to 240 deg c so they are primarily used in the microwave and in the oven. In the microwave ezi seal lids are not only a splatter gaurd but they help to push the heat more evenly and quicker into the food. the 26cm, 20cm and 15cm are a perfect size for any microwave. No BPA so they do not leach. I the oven they replace tin foil, the large rectangle ezi seal lid is the best for this. On the stove top the larger 30cm and 35cm ezi seal lids can be used on top of fry pans, The smaller ones on pots. If your in the caravan, leave the pot lids at home and pack a set of ezi seal lids. If you also buy the 5 back of fresh lids you have the ultimate in innovative kitchenware silicone food covers. We do infact supply a small combination pack and a large combination pack.