YoLinkX3 Version Smart Water Leak Protection Kit: X3 Valve Controller, Bulldog, (4) Leak Sensors & Hub

What technology does it use to deteck water leaks for?specifically outside spigots

what kind of sensors do I need for yolink X3 if need moore?

Where can I purchase a 2nd valve controller to control 2 water valves (hot and cold)?

Can this contact me over the internet on my iphone if water leak is detected and I am away at work. If leak is before valve there would be floodin