Leak sensors have no speaker and make no sound.
Hub generates an audible alert when leak is detected and also sends app notification to phone. The hub’s alert tone may not be loud enough for multi-floor homes. My hub is centrally located on the middle of 3 floors. I can’t hear the hub’s leak alert on upper and lower levels. I’m running Honeywell sirens plugged into Wyze Plugs triggered by the Hub to compensate. It’s saved my butt twice now.
If user has Wyze Home Monitoring subscription and Leak Sensor is assigned to Noonlight active monitoring, Noonlight will also text/call user’s registered phone number. Some insurance companies provide an insurance discount for this feature.