PDF Page Size Split is an Acrobat plug-in tool for full commercial version of Acrobat which is used to split pdf pages on page size, so for example you could have a PDF with 15 pages of A3 and 5 pages of A4, PDF Page Size Split will split the pdf into two files:- one for A3 and one for A4 pages, then you can print all the A4 pdf's without interruption or store them away in your archives on page size, this also makes viewing pdf's much easier.