Carbonation Stone 150mm x 1/4' threads (0.22UM)1. With G 1 4in NPT male gas inlet, it's a great tool for brewing beer for home or bar. 2. Made of high quality stainless steel material, environmental protection, non toxicity and durable. 3. It is an easy way to carbonate your fermented beer. 4. Easy to clean and use, remember to clean and sanitize stones thoroughly before and after each use. 5. Carbonation stones, typically an accessory found on brite beer fermentation tanks, are designed to be