Big Fogg heavy duty stainless and brass compression fittings are used in our high pressure stainless steel misting system applications. These misting compression fittings are dual ferrule fittings designed to compress on hard tubing and hold without leaking even with a high pressure misting pump operating at 1000 psi. Big Fogg suggest using 2 wrenches to secure the brass compression ferrule to the tubing. Please pressure test the tubing when you are finished checking the misting system for leaks. If there is a leaky fitting, add a little our metal fittings are nickel-plated brass. Full ID tube flow is always more torque to the fitting for security and that will stop the leak maintained for maximum Cv ratings and quick cycle times.