It's a digital manometer and it has 11 units, including psi, mbar, inches
of water, inches of mercury, etc. The spec says that it can measure pressures
up to 55" of water, which is much too high for our purposes, and I wondered
whether it would work with pressures down to 1". But as it gives a digital
readout it should do. So I bought one to try it out.
The answer is YES you can easily measure pressures down to 1", in 0.1"
increments. I've tested this by gently blowing down the tube.
It can measure absolute pressure and the differential pressure between two
points (so you can check for leaks, or for wind channels that are are too
small). It has a Hold facillty and a Recording facility, and other features
which aren't needed! It can measure vacuums as well.
So, all-in-all, this is something which will turn out to be very useful,
and much more convenient than fiddling about with plastic tubes full of water
- And it also works upside-down!
At £22 (current price) it's quite cheap, and you get a selection of
plastic tubes with it and a carry bag.
Here is the link to the UK Amazon site, but I'm sure it is available in other
countries (and from other sellers):
from Amazon UK