here is my reply from the guy selling it!
GeorgiesWarehouse sent you a conversation on July 05, 2011.
Singer "Sphinx" Treadle / Electric Sewing Machine, listing #72764663
Hello.
YES,this is a reproduction. These where made in the 1970's.
Singer took designs from their model # 15 and #15-91 to combine the best of both, in a treadle machine with strength and nostalgic beauty.
We added a new motor. Now days people want more than just a, "Show Piece".
It will sew with treadle power, but it is so nice to be able to sew a foot long seam in 5 seconds, rather than 5 minutes.
It has a regular drop in bobbin. Just like the #15-91 model.
Hope this information is helpful.
Enjoy the day.
Georgie