It is based on a flashable controller utilizing the same ARM7TDMI core already used in the 2008 revision of the 12C but in a different package,[3] an Atmel AT91SAM7L128-AU[4][5][6][7] running an emulator written by Cyrille de Brébisson to execute the old HP Nut code much faster than on the original hardware.

This model is powered by two CR2032 batteries, and can easily be differentiated from the original model by the "Limited Edition" script below the company logo as well as the black text on brushed metal back label, as opposed to the white text on black of the original.

The power consumption of the processor is greater than that of the original HP-15C, as HP did not use the same technology in any of the future models.

The initial firmware incorporates fixes for the known bugs from previous models (as shown below) and others;[11] it is emulated on the same CPU[12] as the 2015 and 2022 variants of the HP-12C, the Microchip ATSAM4LC2CA (ARM Cortex-M4).

A fourth choice (4) is undocumented and permits to enter two hidden modes: "15.2" (more memory, but with some limitations like 8×8 inversion matrices and three-digit step number display) and "16" (emulating a HP-16C).