The HP 12C is the industry standard RPN financial calculator produced by HP. It has been in near continuous production with various hardware revisions since it’s original introduction in 1981.

HP 12C

NUT based models

HP 12C (NUT)
 
Introduced1981
SuccessorHP 12C (2008), HP 12C Platinum
Programming
Programming language(s)Keystroke
Other
Power supply3x LR44 (AG13)

ARM based models

2008 model (HP 12C+)

HP 12C (2008)
 
Other namesHP 12C+
PredecessorHP 12C (NUT)
CPU
ProcessorAT91SAM7L128
Programming
Other

30th anniversary edition

HP 12C 30th anniversary edition
Programming
Other

2015 model

HP 12C (2015)
Programming
Other

HP 12 Platinum

HP 12C Platinum
CPU
Processor6502 based microcontroller
Programming
Other

25th anniversary edition