This SAE Standard covers material, dimensional, and performance requirements of steel O-ring face seal fittings for tubing and the O-ring face seal interface and nut portion of hose stem assemblies for nominal tube or hose diameters 6.35 mm (0.250 in) through 38.1 mm (1.500 in). These fittings are intended for general application and hydraulic systems on industrial equipment and commercial products, where elastomeric seals are acceptable to overcome leakage and variations in assembly procedures. These fittings are capable of providing leak proof full flow connections in hydraulic systems operating from 95 kPa (28 in Hg) vacuum to working pressures shown in Table 1. Since many factors influence the pressure at which a hydraulic system will or will not perform satisfactorily, these values should not be construed as guaranteed minimums. For any application, it is recommended that sufficient testing be conducted and reviewed by both the user and manufacturer to assure that required performance levels will be safe. See Figure 1.