Size-1/2" male thread plug, this is a Nominal Pipe Size, and it Does Not represent the actual diameter. Function - Brass pipe plugs to prevent leakage of air, steam, gases, water, oil and fluids under pressure. Material-It is made of high-quality brass forging, and does not leak water. Brass itself has high corrosion resistance, low magnetic properties and high temperature ductility. Work-range of working temperature：-65 to 250 Degree F. The maximum working pressure: 1000 PSI . Applicable scene：Great for blocking off intake manifold water ports, water pump ports, water temp and oil sender holes, engine block.