Summary: BUY THIS ONE FIRST. First of all I need to do math involving Inductor Resistor Capacitor Time Constants This involves millions multiplied times billionths. (20,000,000,000 times 0.000,000,000,200 etc.) The end numbers don't need to be better than 5 places but it is the devil is in the details getting to those 5 digits. If you do metal fabrication you know that steel prices are like gas prices and seem to be interlocked.
Summary: Compact, durable desktop calculator. Could 10-key on this if desired. I even bought another, smaller version of the same calculator. This one is preferred. Just like Goldilocks, not too big, not too small. Just right. If you need a tape, that would be the main drawback. But as a desktop unit for simple bookkeeping, would highly recommend.