PDF of about 25.4 KB for the 3SK303 semiconductor, filed in the schematic category. The file name holds only the part number. Under JIS rules a 3SK device is an N-channel FET with four terminals, a designation commonly applied to dual-gate MOSFETs in tuner and receiver front ends. The sheet is useful to confirm which pin is each gate, the source and the drain, and to compare gain and voltage limits with a candidate replacement before soldering it onto the board.
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.