just a bag.
SYNEK cartridges are the first ever flexible packaging that can withstand the pressures of beer and other carbonated beverages. Three patent-pending primary layers keep your beer tasting fresh for 30+ days. Fills like (and therefore provides the access and variety of) any to-go vessel; preserves and serves like a mini-keg.
The inside layer is an FDA-approved, food-grade lining that doesn’t react with the contents (which means your beer won’t taste like a metal spoon or plastic toy). Then a multi-layer of stretched aluminum provides oxygen barrier qualities similar to cans and protects your beer from UV rays (sunlight + beer = bad beer). Finally, the cartridge's outside layer is coated with a strong plastic-like polymer that adds additional strength and durability. Treat your beer right. It only deserves the best.