The HP-10B (F1636A) is a student business calculator introduced in 1988. The model of this calculator proved to compete well with the higher end RPN HP-12C.
Two versions of the 10B were produced, the first version came with orange lettering around the keys, the later model (in 2000) with teal-green labels. The functionality of the two versions appears to be identical.
The successor HP 10bII (F1902A), which was introduced in 2001, is essentially a cosmetic upgrade offering the same overall functionality, but actually reduces the available numbered-storage registers from 15 to 10. Early production runs were of poor quality; newer calculators have apparently solved this shortcoming.
In 2011, the 10bII was replaced by the HP 10bII+ (NW239AA) model 1 with expanded capabilities. This model also allows chain input. The 10bII+ uses a flashable Atmel AT91SAM7L128 processor with ARM7TDMI core.
In 2015, the internal hardware of the HP 10bII+ changed to use an Atmel ATSAM4LC2CA processor with ARM Cortex-M4 core. The part number and physical appearance of model 2 didn't change except for a "Rev 2" plate on the bottom side. The serial numbers of the new model start with "PHA". The 2×3-pin flash port now uses the USB protocol instead of a TTL serial protocol.
None of the five models supports RPN.