Simplex 4100-1246 Flex-35/50 Class A Adapter Module converts three on- board NACS to Class A operationSimplex 4100 1246 Flex 35 50 Class A Adapter Module converts three on board NACS to Class A operation. 4100ES Audio Systems provide voice communication, alarm tones, and or digitally prerecorded voice messages to alert occupants of fire or other emergency situations. Evacuation signaling may be automatically generated via alarm initiated event programs or by firefighting personnel using the operator controls. Additional information Weight 1 lbs Series