The draft right is still available as most of those old "vintage" Bacharach tools.
It's only designed for taking the draft reading of a chimney/flue vent at the furnace breech or over the fire (but be careful not to burn your fingers)
Insert the sample tube into the back of the gage, insert into flue, place a finger over the other hole that's on the back and level the gage until the indicator "zeros" out. Once the indicator is on the zero, remove your finger and the amount of draft will be shown on the dial.
I'm not sure it has the range needed to measure duct pressures, and it certainly does not have a "pitot" tube.
keep your ice cold and flame hot