The First Alert BRK ADF-12 Smoke Alarm Adapter Plug 12pk easily connects tp competitive Firex alarms without rewiring. This product is compatible with BRK and Firex Smoke Alarms and saves time and installation costs when retrofitting existing homes or apartments. Compatible First Alert BRK alarms: SC9120B 4120-series 9120-series 7010-series 5919 2002RAC SC6120B HD6135FB RM3. Compatible Firex alarms: 406 (G-6) 4518 (ADC) 4618 (FADC) 484 (PG-40) 4480 (PAD) 5700 (ADH) 499. Maximum of 18 units total may be connected (12 Smoke Alarms plus 6 other devices.) First Alert designs and creates safety products that preserve and protect the things that are the most important to you from your children and family to your home and the priceless memories stored inside. BTI trading was established in year of 2012.We are allocated at US WA.The transportation to our store is very convenient.we are selling only high quality products we also selling our products world wide .At BTI we sure you can find all the product that you want.