Extra Pretty and Nicely Designed Old Abacus with Hand-written Numbers

I love an abacus, but there are a lot of them out there and I usually make myself let them go. This, though, is the loveliest abacus I've seen in a long while, with an unusual recessed design, and a nice softness to the color on the wooden beads. Plus someone long ago wrote numbers in increments of ten down the left side in red, and scribbled a few other things on it as well, making it warmly personal in addition to beautifully minimal, to me a very nice combination. 

9 1/8" x 7 1/4" and in good condition, with writing and scribbles as noted and documented.