The hp20s is a well build basic calculator that will last through years of use. It was a low end model when it was introduced by HP and doesn't have RPN or any advanced math features, but what it does have is 99% of what most people need in a handheld calculator in a nice package. HP's and TI's latest lower end models are plastic junk in comparison.
Buy it if you can find one at a decent price...Get more detail about HP HP20S Scientific Calculator.
