2 1/2 inch NH / NST barrel strainer with poppet style check valve. Female threads do not swivel. NH / NST threads are used by most fire departments.
A foot valve is essentially a check valve that is integrated into this aluminum barrel strainer which is attached to the inlet side (suction side) of a water suction hose to keep it from losing it's prime during the off cycle. This can drastically reduces water relay time. It can also be back filled to aid in obtaining pump prime if suction pump is weak.
Comes with eyelet on the cap to attach a line for easy retrieval and maneuvering.