From the product description, check product page for current description, price and availability:

• Food-grade Material — Made of premium food-grade mylar aluminum foil, which is high & low temperature resistance, water proof, smell proof, strong, durable, so they can be heated at high temperature or stored at low temperature, nice to to meet your long term dry storage requirements.
• 3 Size for Choosing — 3 sizes of foil bags are included, that is 5pcs foil bags with the size of 10*14 inches, 10pcs foil bags with the size of 8*11 inches and 10pcs foil bags with the size of 6*9 inches, meeting almost all your sizes need.
• Long Term Storage — These mylar bags for food storage can prevent food from spoiling and extend the storage time of food. And they have good material and high quality that can protect the food from external weather changes.
• Widely Application — These reusable food bag are vary suitable for storing cookies, coffee beans, tea, dried flowers, dried fruits, grains, seasoning, dried food, nuts, powder, candies etc. And they are also suitable for packing, storing, sampling and sorting.
• Easy to Use — These mylar bags are reusable and heat sealable, so you can use the heat sealing machine (not included) to seal the bags, and can reseal after opening. And they can also be vacuum sealed and there is a u-shaped hole on the side of the foil bag for easy tearing.

From HBF: Make sure the components you use are compatible and rated for your intended application.  Contact manufacturer with questions about suitability or a specific application.  Always read and follow manufacturer directions.