All of the following AVANTEK doorbells with plug-in receivers can be paired with each other: CB-11/CW-11/CB-12/CW-12/CB-21/CW-21/D-3B/D-3W/D-3G/D-3F/D-3C/DB-21 (For orders purchased before 2021, it is best to tell us to inquire whether they can be paired.)