The Series 6401-O Straight Male ORB x Male NPT hydraulic adapters, made from durable carbon steel, are designed to provide secure and leak-proof connections in hydraulic systems. These adapters feature a male ORB (SAE Straight Thread O-ring Boss) connection on one end, which uses a straight UNF thread and an O-ring to create a leak-tight seal when compressed against a smooth, flat surface with a chamfer. This O-ring design, recommended by the National Fire Protection Association (NFPA) for medium and high-pressure systems, ensures reliable performance in hydraulic applications. On the other end, the male NPT (National Pipe Taper) connection features tapered threads that create a strong seal through thread deformation, ideal for fluid and gas transfer. The nominal pipe size is determined by measuring the thread diameter and subtracting 1/4". While NPT connections are suited for single assembly applications, they are not recommended for frequent disassembly due to potential thread wear. These adapters are perfect for professionals seeking dependable, high-quality hydraulic solutions in various applications.