My rating is based on the fact that the first fitting I fitted (-16 AN) shows signs from fatigue on the pad exhibited the nylon jaws (small, localized, white deformity). This was not due to over-tightening of the fitting, but to the torque applied to the fitting during screwing in. I should add that the pre-assembly was lubricated with anti-seize compound on aluminum to prevent galling and internal threading. Rubber was lubricated with silicone (Silglid). This was done at ambient temperature (88 F), which was enough to indicate the rubber was soft enough to build. It might be a harsh criticism, but it's factually correct.