I handle plenty of documentation for the training of our pilots in my company and part of those hand outs are materials requiring 4 or 7 holes punched.
We use Leitz Akto 5114 Perforator for our punching needs. Our puncher is the heavy duty kind where you can do endless of manual perforation and the dies are still sharp as ever.
This perforator can be customized to accommodate dies for 2, 3, 4, 7 or more, depending on the requirement. It comes with spare dies should you need to add more or replace a rusty or broken one.
It has a lock mechanism so you do not accidentally punch your documents. Also, a scale is placed on the feeding dock so you can position your paper accordingly.
It can accommodate at least a maximum 10 to 15 pages in one go depending on the paper's grade.
It is rather heavy considering its purpose for punching plenty of documents. It also has a plastic catch on the bottom for the excess cut outs.
We have been using this puncher for many years and it still perforates sharply and it must have punched millions of papers already. We are sticking to this heavy duty puncher for sure.