This trapets adapter in nickel plated brass allows you to attach 425 g aluminum CO2 cylinders to a CO2 regulator with standard W21.8x1/14" threads.Version 2.3 features a spring pressure screw, that makes it no longer necessary to make adjustments for different brands of CO2 cylinders in most cases.Comes equipped with a safety vent hole to minimize the risk of damaging the gasket when unscrewing it from the CO2 cylinder with remaining pressure.Made in Sweden.