1904 Singer Minature Model #J-4 Sewing Machine

This is very interesting. This sewing machine was brought over by my neighbor to see if I could find any information about it.  It belonged to her grandfather that recently passed away and every sence she can remember it has always been on the mantal at his house. This looks to me like it is a salesmans copy or prototype of what the full size ones are. The only thing that is on it is a small engraving that  reads as follows: SINGER, MODEL J-1, 110 VOLTS, 60 CYCLES, 48 WATTS.   It has a motor and a plug in. I have plugged it in and it works. It sews just like the ones that are made today.  Any info or value would be very much appreciated.

Fair