All of SUPERLOK Tube Fittings, design and dimension, are similar to LEGACY BRANDS and Parker. Tube Fittings are fully interchangeable with these brands. Similar form, fit, and function. The Nut and body threads of a SUPERLOK fitting OD are constructed in accordance with ASME B1.1 and the thread tolerances are controlled as specified in ASME B.1.1. This strict tolerance ensures a consistent make-up every time. As proof, we have attached the “SGS intermix-ability & interchangeability burst-test certificate.