A 98.4 KB PDF titled with the part number 2SC4162, filed under schematics but in practice expected to be the datasheet for that transistor. Japanese JIS numbering uses 2SC for NPN bipolar transistors, and the shortened code C4162 is what normally appears on the package. The sheet supplies terminal identification, mechanical outline and electrical ratings, which matter when testing a suspect part or sourcing an equivalent for a power or signal stage. Check the suffix letter and case on the original since the name states no gain class.
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.