FXN922 is a Multi-Mode Detector, has 5 different modes within a single detector. This multi-mode detector can be configured to operate as either an optical detector, opto/heat multi-sensor or 1 of 3 heat detector modes (A1R, BS, CS) using the four position switch located at the back of the detector. The detector has a dual LED indicator – the red LED is lit continuously to indicate alarm condition, the amber LED when lit continuously indicates that the detector has reached the limit of its contamination compensating ability.