You don't need to pay this high prices for the Racor vacuum gauges. I use and install gauges sold by Sailors Solutions
which feature a drag needle.
Keep in mind that in order to take an accurate vacuum gauge reading you need to be under load at near wide open throttle, kind of a PITA. A drag needle allows you to view the highest vacuum recorded without having to even stick your head
in the engine compartment with the motor
running, as it is recorded for you to see any time.
The gauge from Sailors Solutions is of very high quality and less money
to boot. This one is actually mounted to a 900 series Racor.. I choked down the shut off valve for the photo
to show the red drag needle..