how much? depending on packaging, $10, $15. not bad it does everything. this is coming out in august, first alert, voice, smoke alarms. good for families especially. first alert showed surveys show kids pay more attention to a voice than the alarm beeping. so, if these go off they re going to be sold in pairs or multiple units. and they work wirelessly? wirelessly. when you first plug it in. hit the button when it says what room you are putting it in. the alarm goes off in the bedroom. it sounds all the alarms throughout the house. but each alarm says, the emergency is in the bedroom. identifies through voice where the emergency is. yes, exactly. that is so helpful. and they re also going to have a combination of smoke and carbon monoxide detectors. august. we like that. we have a problem sometimes. surge protectors lie flat on the ground. put the plug in.