With both solar and battery power sources, this calculator is convenient for use on the go. The regular key size and scientific type make it ideal for solving complex equations and graphing functions with ease.
Casio FX-991CW the best calculator I have had - so far
Online manual is ok but the pdf version is better.
The physical constants are not explained as to their meaning. Maybe Casio assume if you need the value you'll know the symbol and the units. I noticed at least one value is fractionally different from the latest values.
I hope the next generation of calculators will have units and unit conversions built into the arithmetic e.g. X feet squared times Y psi equals Z kN per metre squared.