Brennan Industries”double-ferrule, instrumentation-grade tube fittings provide leak-proofand torque-free seals at all tubing connections. The fittings aredesigned to reduce the chance of hazardous and expensive leaks ininstrumentation, process, pneumatic, hydraulic, gas, and other tubingsystems. The fittings consist of the nut, the back ferrule, the frontferrule, and the body. When installed they provide a five-piececonnection with the addition of the tubing providing a solid leak-freejoint. The two ferrules are tightly swaged around the tube and the lackof initial strain on the tubing ensures no tubing wall damage. Leaksare prevented because there is an axial movement along the tube insteadof a rotary motion creating the joint. This axial movement preventstorque from being transmitted from the fitting to the tubing. Resistantto temperature change, the fittings do not significantly reduce flowarea and work with a variety of tube materials. In addition, thetwo-ferrule action supersedes variations in the wall thickness,hardness, and dimensional tolerance of the tubes, ultimatelycompensating for most variables that lead to failure with otherfittings. Brennan double ferrule compression tube fittings can beremade several times and can withstand heavy impulse and vibration inboth vacuum and pressure systems. Requiring no special tools forinstallation or torque for initial makeup and using only geometry, thefitting requires 1.25 turns until it is tightly fitted.