The Series 6405-O Straight Male ORB x Female NPT Rigid hydraulic adapters, made of corrosion resistant stainless steel, combine the benefits of ORB (O-ring Boss) and NPT (National Pipe Taper) fittings for reliable, leak-free connections in medium to high-pressure hydraulic systems. ORB fittings feature a straight UNF thread with a compressible O-ring that forms a tight seal against a smooth, flat surface in the female port. This O-ring compression ensures leak prevention, making ORB fittings ideal for applications requiring secure connections, as recommended by the NFPA. Meanwhile, NPT connections use tapered threads to seal pipes by deforming the threads together, making them suitable for fluid and gas transfer. These adapters are engineered for single assembly use and provide long-lasting, high-performance sealing for various hydraulic applications.