BRK Electronics First Alert ADF Adaptor plugs to replace a Firex Smoke Alarm (pack of 1)

All of the listed BRK and First Alert Alarms are compatible with the listed FIREX Alarms and will work with the enclosed Adapter Plugs.BRK Alarms: 4120, 9120 Series - AC, AC/DC Ion, Silence 5919 - AC Photo 2002RAC - AC/DC Photo 7010 Series - AC, AC/DC Photo, Silence SC6120B, SC9120B - AC/DC Smoke/CO Combo HD6135FB - Heat Alarm RM3 - Auxiliary Relay FIREX: 406 (Model #G-6) - AC Ion 4518 (Model #ADC) - AC/DC Ion, Battery in Rear 4618 (Model #FADC) - AC/DC Ion 5000 (Model #FADC) - AC/DC Ion, Latching LED 484 (Model #PG-40) - AC Photo 4480 (Model #PAD) - AC/DC Photo 5700 (Model #ADH) - Heat Alarm 499 - Auxiliary Relay Maximum of only 12 units (except model G-6) may be interconnected. Check for model numbers above.