From KK Technologies:
KK-12C is the ultimate programmable financial calculator for Palm OS.
KK-12C emulates the functions of HP-12C / HP 12C Platinum, the most popular financial calculator ever, with extra features.
Program and all other registers can be saved at any time with unlimited sessions. More over, KK-12C comes with familiar look and feel of the real HP-12C, but fits nicely on your Palm screen. Requires Palm OS 3.5 or later and 200K of free memory for standard version, and 450K for High-Density display version (HD). HD version supports display in double-density mode (320x320), and full screen display on handhelds with landscape (320x480) mode