STRONG REUSABLE Zipper: The resealable bags are designed with a super strong zipper. You can either manually seal the zipper part, or you can heat-seal the open top above the zipper, achieving a storage effect. These food storage bags can be used many times. CONVENIENT TO USE: Simply open and seal the zipper part; very easy to use for packing and storage. The transparent frosted front window design allows for a quick glance at the contents inside. Ensure you close the zipper seal tightly to prevent leakage and maintain freshness. PREMIUM QUALITY MATERIAL: These sample bags are made of polyethylene, aluminum foil, and mylar, a composite of high-quality materials. They are durable, non-toxic, and tasteless. WIDE APPLICATIONS: These packaging bags are perfect for storing food items such as coffee beans, cookies, tea, nuts, dried fruit, and snacks. They can also store smaller items like lip gloss, eyelashes, samples, jewelry, electronics, crafts, etc. Color: black Material: Aluminum foil + polyester film Package Contents: 100 * Smell-proof Mylar Bags 3 x 4.7 inches 100 * Smell-proof Mylar Bags 4 x 6 inches 100 * Smell-proof Mylar Bags 4 x 6 inches 100 * Smell-proof Mylar Bags 4 x 7.9 inches Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3 cm.