You are right that OSBee is a standalone controller with 3 zones. It’s based on ESP8266. You can have the main OpenSprinkler communicate with it via HTTP zone feature — i.e. set one of the OpenSprinkler zones as a HTTP zone, and make use of OSBee’s API to allow main OpenSprinkler to open or close zones on OSBee. Unfortunately at the moment OSBee is out of stock and we do not plan to restock it anymore. So the closest alternative, for latching valve, would be OpenSprinkler Latch.