Touch RPN, formerly known as Touch Fin, is an RPN calculator. This app implements many features of the industry-standard HP-12C.
This app offers many additional flavors of RPN calculators, including financial, scientific and for computer programming.
Two flavors are available for free (ad-supported): financial and scientific. Additional ad-free flavors are available for purchase within the app. The purchased flavors also offer vertical layout and saving memory to files.
Press the ON key to change Settings, choose the active flavor, and purchase additional flavors.