[Size & Quantity] 50 PCS food packaging coffee bags empty, thickness of 28 wires, aluminum foil flat bottom resealable side zipper smell proof bags with one-way air valve. [With one-way air valve] The one-way air valve keeps the coffee beans and roasted coffee fresh. Excess air flows from the inside to the outside and does not flow back, keeping food fresh. [Functions] Household: Suitable for packaging various products, including kitchen ingredients, food and other daily necessities; Commercial: You can attach your own brand label on the surface as a retail or sample display package. [Heat Seal Demo] 1. Put the items in the bags. 2. Must use heat sealer machine(not include) to seal the top of the bag(occasionally not completely sealed, can turn the bag over, heat seal again). 3. Squeeze the air out of the bags through air valve. Size (width x height+bottom spread):A:9x18+7cm/B:13.5x26+7.5cm/C:13x20+7.5cm/D:15x32.5+10cm Color:Black Material:Aluminum Foil Package Contents: 50 * Coffee Bags with Valve Only the above package content, other products are not included. Note: Light reflection 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 +/- 1-3cm.