It's not been professionally reviewed, but the handful of user reviews we spotted scattered on sites across the internet have largely been positive thus far. For example, though the totals are lumped in with the First Alert SA320CN at Amazon, all but 4 of the more than 30 that weigh in on the SA3210 specifically grant it either 4 stars or 5. Among combination smoke and carbon monoxide alarms, the First Alert SCO501CN 3ST Est. $50 looks like a top choice. Like the First Alert SA511CN2 3ST discussed in the section on photoelectric smoke alarms, the SCO501CN 3ST uses radio technology to set up a wireless network with other First Alert interconnectable alarms smoke, CO or combination without the complications that a hardwired interconnected alarm system would entail, though you might need to experiment a little with alarm location to make sure that each unit is within range of at least one other interconnected alarm. Reviews of the First Alert SCO501CN 3ST are mostly strong. It receives a recommendation from Consumer Reports for its performance as a CO detector, but only a middling rating as a smoke detector as it only has photoelectric sensors for that function once again, Consumer Reports only recommends smoke detectors with both types of sensors, though not all experts agree that those types of alarms are the best option. Still, the SC501CN's performance earns the highest possible grade both when it comes to smoldering fires, and as a CO detector. It receives top ratings across the board for detecting high concentrations of CO, low concentrations of CO and the quality of its alerts. The Kidde KN COSM BA Est. $35 is also worth considering.