Despite what the manual says and unlike the older non-plus models, the external contacts DO NOT work. See the first review reprinted below. I have a couple myself and I can confirm that they are non responsive.
Doesn’t work with external switches
This sensor, like the non-plus version it replaced (PID 10795) and the non-plus garage door sensor (PID 11987), has terminals inside to connect an external switch and instructions on how to use it in this fashion. A common use case would be to add z-wave functionality to existing wired reed switches many houses have from legacy security systems.
Unlike those other Monoprice z-wave sensors, the terminals on these don’t actually work. I ordered 4 and none read “closed” when the terminals were shorted. Monoprice replaced them with four new ones, none of which worked either.
Product support then confirmed that this was a design issue and should be updating the documentation accordingly. They said a redesign would be unlikely.
So be warned if you want to use the terminals inside these new z-wave plus sensors as they aren’t functional.
Otherwise, the sensor worked with the included magnet as expected. Can’t speak for the “plus” features as I didn’t hold on to them long enough to evaluate battery life and I have no range issues with my existing sensors.