Yea, I know the problem! almost all carbon monoxide manufacturer refused to do anything about visual alert. They simply refused, I have contact many of the detector manufacturer, the response I got was... "We don't have any plan to add this to our line". Sure, there is limited sources where there is flasher, but unrealiable one, they depend on transmitters. I rather have build in flasher to ensure its realiablity. I do have Gentex smoke detector, and actually asked Gentex if they manufacturs the carbon monoxide. The answer is NO, and not planning to do so. If they had one, I can tie them up with my tandem smoke detectors.
Politicans don't give DAMN about this!
BTW, almost happened to me, and my family. Glad I caught it in time!
Im still pissed off at these lazy manufacturers and politicans. Sure, in NYS, they require to have carbon detector installed on EVERY DAMN house sold, and that the flasher isn't require even the buyer's is deaf!