This Duotight fitting is great for anyone who needs to connect gas or beverage lines. Whether you're a homebrewer or a professional in the beverage industry, it's a must - have. The fitting measures 8mm (5/16 in.) x 1/4 in. It can be used to connect flared gas and beverage ball lock and pin lock disconnects, as well as connect gas lines to MKIII and KOMOS CO2 regulators. With its double O - ring design and no - clamp requirement, it provides a reliable and easy - to - use connection solution.