oh, since your going with the Univer that will work just fine. Univers can be cal'ed for draw through or blow through, but from the reviews ive read, people seem to have better luck with the blow through meters, where as the draw through Univer has had some neggitive feedback.
It's simple.. You buy a Univer blow through cal'ed for 42's blow through, and your done!
ProM is under a new name and ownership, so yes you can still buy and have ProM's recal'ed. They might have started selling the Pro Solutions meter, which is a cheaper alterntive to the Univer.
I forget the new name.. Im wanting to think it's mass air systems, professional mass air systems, or something along those lines.