PeBe I tried it with the RF bridge from sonoff, the connection works as it should. When you press TEST it works, a message arrives on your mobile.The problem is that the device does not react to smoke, the product also does not have a trimmer for sensitivity adjustment. I tested it in dense smoke and for a long time, with no result.

PeBe How to pair a water sensor with RF BRIDGE:It works great. In the EWELINK application where you have RF BRIDGE, click on RF BRIDGE and then click ADD remote, then ALARM and confirm, then on the newly created remote hold your finger for at least 5 seconds on the bell mark (you will hear the sound). RF BRIDGE will wait a minute to add a WATER sensor. In a minute you have to connect the contacts on the sensor, for example with a cutlery knife :) (you will hear the sound again, the pairing sound) This will make a short circuit, as if the contacts are connected by water. Then the connection is complete