High Quality – Made of stainless steel material, providing durability and longevity. Heavy-duty construction with a perfect polish for extended use and easier carbonation of beverages. Cost-Effective Carbonation Tool – Compatible with PET bottles, gas (grey) ball lock connectors, and liquid (black) ball lock connectors. More portable and convenient compared to CO2 systems. Easy to Use – Attaches to plastic bottles and connects to a gas-side ball-lock disconnect to inject CO2, enabling quick carbonation. Enjoy carbonated beverages in less time. Versatile Usage – Carbonation caps can be used to carbonate various beverages, including beer, soda, water, and juice. Also suitable for cleaning beer lines and counter pressure bottle filling. 100% Satisfaction Guarantee – ProMaker high-quality carbonation cap includes 4 extra O-rings in a small bag. Replace O-rings if wear occurs over time to prevent leaks. If not satisfied, return the product for a full refund.