This raw water strainer is used for the engine raw water intake on most early inboard equipped Catalinas. Exceptions are likely the very first few inboard boats Catalina built as well as those like the Catalina 42 with larger engines which require more water than this strainer's capacity. In later Florida built Catalinas with electric heads, this strainer is used on the raw water supply line just upstream of the electric pump.
The only distinguishing marks are very tiny "PPA" and "NYLON" on the bottom of the clear cup and "1/2 NPT" with an arrow indicating the direction of water flow molded into the black housing.
We routinely have requests for individual components for this strainer. But the clear cup, the strainer, and the "O" ring are all subject to failure. Purchasing the three spares individually costs more that the entire strainer. It makes more sense to simply carry a spare strainer aboard so all of the parts are available in case of an emergency. We only carry the strainer element as a replacement part (see "May we also suggest" below). We don't carry any other replacement parts individually. C-355, C-375, C-385, C-445