A 44.4 KB PDF titled 181nq, categorised as a schematic but almost certainly the datasheet for a high-current Schottky rectifier module family; no voltage suffix is given, so it likely covers several grades. Such documents give average forward current, forward drop versus temperature, thermal resistance and mechanical outline. A technician refers to it when a module in a large power supply or charger has failed and a matching or uprated part is needed. Read the full code on the module before choosing a grade.
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.