Three side seal bag is the earliest bag type in heat seal packaging line, it is widely used before side gusset bag, stand up pouch and flat bottom pouch. Whether before or now, three side seal bag also has big packaging market . For Union Packing, three side seal bag still own 30% of the production and can pack food snacks, nuts, spice, candy, beef jerky, seeds, tobacco leaf, toy, cosmetics, metals, socks, underwear, masks and etc. Three side seal bag is simple and low-cost, small and big, easy to use and carry, so it has so many faithful and old customer.