Named 16RIA, this 226 KB PDF is catalogued as a schematic but appears to describe a component series, with no device, board number or revision in the name. The code resembles International Rectifier thyristor series naming, so the document probably covers several voltage grades in one datasheet with ratings, gate characteristics and stud or case drawings. It is useful when replacing a power thyristor in industrial or supply equipment; match the full part code and mounting style on the original before substituting.
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.