... 433Hz optional,use battery,easy use,sound activated,factory offer baby monitor,wireless baby camera,audio baby monitor,315Hz/433Hz optional,use battery ... Remote Range:50-80M (in open area);Sound Activated: place Transmitter near Baby,Receiver near or together with Mom/Dad. ... Once baby is crying or other sound,Receiver will be activated to sound imitated baby crying;Sound Level: 92±5Db; ...