Brassomatic brass compression fitting is a 3-piece fitting consisting of body, nut and sleeve-furnished assembly. Sleeve is made of hardened brass and bites into outer surface of tubing assuring a tight joint even though surface of tube is rough.These fittings withstand severe vibration because of multiple points of tube support in the fitting. These are. At the back of the nut and the bevel of the sleeve.At the cutting end of the sleeve.At the shoulder in the base of the body.