Plug adapters are fittings used to seal or block off ports in hydraulic and fluid power systems. These adapters are designed to securely fit into open ports, preventing the flow of fluid or gas, and are typically used for maintenance, testing, or system assembly. Plug adapters come in various thread styles, such as NPT (National Pipe Tapered), JIC (Joint Industry Council), or ORB (O-Ring Boss), ensuring compatibility with different components and connection types. By providing a tight seal, plug adapters help maintain system integrity, prevent contamination, and protect unused ports from damage. These adapters are essential in fluid power applications for ensuring a reliable, leak-free closure, making them a crucial component for maintaining the efficiency and safety of industrial systems.