High Quality – Made of stainless steel material, more solid and long-lasting, heavy duty with perfect polishing for extended use and easier carbonation of beverages Cost-effective Carbonation Tool – Use to counter pressure bottle fill PET bottles, gas (grey) ball lock connectors, or liquid (black) ball lock connectors; more portable, convenient, and economical than CO2 systems Easy to Use – Attaches to plastic bottles and connects to a gas side ball-lock disconnect to inject CO2 into the bottle, creating carbonation; enjoy carbonated beverages almost immediately Versatile Usage – Carbonation caps can carbonate various beverages including beer, soda, water, and juice; also useful for cleaning beer lines and counter pressure bottle filling 100% Satisfaction Guarantee – High-quality carbonation cap includes extra 4 o-rings in a small bag; replace o-rings if worn over time to prevent leaks; if not satisfied, return for a full refund