The HP42s is a high-end RPN calculator in the HP Pioneer line, distinguished by its silicon-on-sapphire Saturn architecture chip code-named "Lewis", and a 131x16 dot matrix display (both were also used on the HP-17B & BII, and HP-27S).
The HP42s is a high-end RPN calculator in the HP Pioneer line, distinguished by its silicon-on-sapphire Saturn architecture chip code-named "Lewis", and a 131x16 dot matrix display (both were also used on the HP-17B & BII, and HP-27S).