PDF datasheet labelled 1n4004a, 90.8 KB, indexed under schematics. It concerns the 1N4004 rectifier, and the trailing a may be a vendor version or document suffix that the name does not explain. The 1N4004 is specified for 400 V reverse voltage at 1 A. Open it in any PDF reader to read maximum ratings, forward characteristics and outline data. Compare its figures with other vendor sheets in the collection if you need tighter surge or leakage values for a particular circuit.
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.