The diagnostic quick coupling plug with shut-off valve and internal NPT thread is a robust solution designed for precise pressure measurement in hydraulic systems. Manufactured in compliance with ISO 15171-1 and SAE J1502 standards, it ensures full interchangeability with connectors from other leading brands, offering flexibility and reliability in demanding applications. Produced from hardened, galvanized steel and sealed with high-quality NBR, the plug guarantees durability, resistance to wear, and secure operation within a wide temperature range from -40°C to +120°C. With a working pressure of 400 bar and a burst pressure of up to 1300 bar when connected, it provides outstanding safety margins, while its flat valve surfaces minimize oil leakage (approx. 0.1 ml) and air inclusion (approx. 0.02 ml), ensuring system cleanliness and efficiency. The plug is designed for permanent installation in hydraulic circuits, while the socket remains connected to the pressure gauge via a hose, enabling quick and leak-free diagnostic checks. Its optimized flow capacity of 4.2 l/min at Δp = 3 bar and vacuum resistance up to 0.9 bar make it a reliable choice for precise monitoring and maintenance of hydraulic systems, reducing downtime and enhancing operational performance.