A 379 KB PDF covering the 2SJ304. The file name holds only the part number, with no reference to a product. The 2SJ prefix of the Japanese JIS system identifies a P-channel FET, so the document is probably a full datasheet including graphs and package information. Consult it for drain-source voltage, continuous current, on-resistance and pin layout. When the original is unobtainable, use these values to pick an equivalent with the same polarity, footprint and adequate margins.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @cyberlanelectonik. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.