The HP-67 is one of the most interesting classic programmable calculators by Hewlett-Packard. As a consequence, they are quite rare and pricy. So, if you do not have the chance to own one, you can download an exact emulator on PANAMATIK Engineering office for hardware and software development’s webpage here: http://www.panamatik.de/html/hp-67.html. Exact means that the emulator runs the original microcode to carry-out your operations. Note that you can acquire many hardware and software tools to repair and use your classic Woodstock HP calculators. If one day I can find another HP-67, I may be tempted installing their low-power kit: http://www.panamatik.de/html/hp_low_power.html.