ERA-DCKIT-2 
On the back of the Carlon/Dimango product, you should see a small white sticker. On this sticker, you will see QC with a four-digit code right under it. The last two digits of this code show the year the product was manufactured. If the number is "00" or higher, then your product will be compatible.
To find a list of compatible Carlon/Dimango Wireless Door Chime buttons, please click here.