1. Freshness preservation: These reusable standing bags have a one-way air valve that allows the flavour gas to vent from inside to outside without air ing, keeping roasted coffee beans fresh. They can also be used to store other foods like snacks, nuts, dried fruit, cookies, popcorn, tea, spices, seasonings, grain, jerky, confections, candy, toffee, chocolate, little bread cakes,Home and Store Organization. 2. Packaging:The pack includes 60 pcs of aluminum foil flat bottom standing bags and side zipper mylar bags, both of which are reusable and recyclable. The bags are designed to help you save money while staying organized, and can be shared with your family or friends as little lovely gift treat bags. 3. Zipper closure design: The bags have a high barrier, side zipper, and are heat-sealable. The top can be sealed with a sealing machine, and the bag's top side has a u-shaped groove tearing port, making it easy to tear open. The bags are also resealable and strong enough to keep your food inside without popping open. 4. Safety: The bags are made of PET plastic and matte metallic solid color aluminum foil film, which are smell proof, waterproof, and food-grade certification qualified. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.