Yes, i’ve a Popp flow stop in use.
But it did not fit on my pipes and tap: my tap is not that closely aligned.
So I’ve mounted the Popp on its own 12 mm pipes and connectors (https://www.tech-specialist.com/nl/buis-rk-rose-krieger-rvs-buis-op-maat-1007377) and these are kept in place against the watering tap.
It is working nicely for my garden watering.
On aliexpress there are more flow stop devices, but they all seem to come from the same factory.
Anyhow, i’m still waiting for a flow stop which will close when there is power failure.
Instead you could use a 230 volt battery, but then the vera has also to be connected to that device.