Brass 2 1/2" NH / NST 45 Degree Elbow Female Threads_NYFD The most common size and

The most common size and threads for US fire hydrants is 4 1/2 inch NH / NST

Forged brass angle hose valve is used with fire hose rack assembly

of 2 1/2" or 3" hose

Meets NFPA 1961 standards

It's usually installed on the inlet side (Suction Side) of a water pump to keep it from losing it's prime during the off cycle

Brass 2 1/2" NH / NST 45 Degree Elbow Female Threads_NYFD The most common size andElbows are used on pump discharge valves or suction inlets to minimize hose kinking. Should also be used when flushing hydrants or other water systems to protect the inner liner of the discharge hose from water pressure or debris damage.