There has been much discussion on adapting or replacing frequency ringers and inquiries about purchasing SL replacements. An eBay seller has a couple for sale cheap!
http://www.ebay.com/itm/280832236530
I wonder what the bracket on that one is from? Doesn't matter, it can easily be removed leaving a ringer with the standard AE mounting configuration but this was obviously out of some phone that I don't recognise.
Terry