System Sensor RTS2 Multi-Signaling AccessoryThe RTS2 and RTS2 AOS multi signaling accessories are designed to work with InnovairFlex 4 wire conventional duct smoke detectors. These accessories include a key switch that can be used to select one of two connected sensors to be tested, reset, or both by a push button switch. They also enable sensitivity measurements using the SENS RDR sensitivity reader (sold separately). The AOS (Add On Strobe) is an optional accessory included with the RTS2 AOS