Folkroots Mountain Dulcimer by Rugg and Jackel.
Label has handwritten "D400S" and "064" below that, on the bottom right of the label.
Appears to be in very good to excellent condition. Beautiful wood grain on back and sides.
A 6 1/2 fret was added at some point.
Not sure how old it is, most likely from 70's or 80's.
photos can also be seen at: https://vermont.craigslist.org/msg/d/folkroots-mountain-dulcimer/6404137523.html