System Sensor’s CO1224TR carbon monoxide (CO) detector with RealTest is a round version of the company’s CO1224T CO detector. This circular version is for ceiling or wall applications where a round device would better suit the aesthetics. Like the CO1224T, the CO1224TR includes RealTest, which is a field-functional CO test fully compliant with NFPA 720-2009. RealTest enables for quick verification that the CO detectors are working properly. The CO1224T and CO1224TR also provide multiple mounting options. The detectors have a low current draw, the latest electrochemical sensing cell, and a six-year, end-of-life timer.