The $69.95 device works with a doorbell that you can attach to any doorframe, and includes a receiver that’s actually an MP3 player. The receiver comes with 32 built-in tones, but you can add your own by placing MP3 files on an SD card.
You really only need a single tone to customise, but if you want a little variety you’ve got the option. Both the doorbell and the receive run off AA batteries. If you’ve got a problematic doorbell or just want one you can customise, check it out.