The Helm USB PDF is encrypted and it's a pain in the a$$ because you can't copy the PDF onto a fast SSD and run it (i get that they are protecting their material), but as TOM said "no bueno" I wanted to put the stick away to protect it.
You can copy the PDF but you have to launch their .EXE (from the stick) in order for it to work. If you just try to launch the pdf by itself (because it's encrypted) the PDF reader will say the file is corrupted. You cannot copy the .EXE to your HDD and run it without the stick in the PC. The stick and the .EXE are tied together, you can plug the stick into other PC's without issue. Once you launch the EXE it uses the stick for the searches and even on a USB 3.X port it's slow compared to a HDD. They also kill using the snipping tool to make it difficult to copy sections and post them. You can print sections or the whole the PDF without issue if you wish. You can also cheat a little and print to a fictitious printer like a "print to PDF" so long as you change the fictitious "PDF PRINTER" name so it doesn't have any reference to printing to pdf.......