This recall involves System Sensor’s reflected beam smoke detectors with model number BEAM1224S and date codes 2111 through 3053. The YMMW format date codes stand for (2111) 2012-November-1st week of Nov. through (3053) 2013-May-3rd week of May. The detectors are ivory and black and measure 10 inches high by 7½ inches wide. The model number and date code are printed on a label on the back of the detector’s cover and on the product’s packaging. The reflected beam smoke detectors were used primarily in commercial buildings as part of the fire alarm system. Detectors used with acceptable power supplies, as listed on the company website, do not need to be replaced.