Alarms and Detectors
CO Detectors w/ PPM Displays and Battery Backup
Although all home CO detectors use an audible alarm signal as the primary indicator, some versions also offer a digital readout of the CO concentration, in parts per million.
Typically, they can display both the current reading and a peak reading from memory of the highest level measured over a period of time.
The digital models offer the advantage of being able to observe levels that are below the alarm threshold, learn about levels that may have occurred during an absence, and assess the degree of hazard if the alarm sounds.
They may also aid emergency responders in evaluating the level of past or ongoing exposure or danger.