The YoLink Valve Controller 2 kit clamps a Bulldog valve robot onto an existing ball valve, so the main water supply can shut off on a leak without cutting the pipe.
The Bulldog robot bolts over the handle of the ball valve already on the main and turns it, so there is no pipe to cut. The controller mounts on the wall nearby and runs on four AA batteries, the included power adapter, or both, with the batteries taking over in a power cut.
It needs a YoLink hub, which this kit does not include: add the YoLink SpeakerHub, or buy the water shutoff kit that bundles the controller with the SpeakerHub and three leak sensors. Home Assistant’s YoLink integration reaches it through the YoLink cloud, so an automation in Home Assistant cannot close the valve while the internet is down. To cover that, pair a YoLink leak sensor directly with the controller, and the valve still closes on a leak without the internet.
YoLink also sells the same controller with a motorized valve that is fitted into the pipe instead.