For your consideration, here is a Janome Sewing Machine Promotional Folding Calculator, 10 digit, 2 power source, battery and solar, made in China.  It has been tested some.  I tried it out with solar, but not battery power.  It works great, with a good display.  It has some light wear on it.  All of the buttons depress correctly.  Item pictured is the actual item up for sale and comes from a non-smoking household.  (364.325e-.7hc)