Brand:  Texas Instruments  
Model:  TI 68  
Type:  Programmable scientific calculator  
Batteries:  CR 2032  
Lifetime: 
Introduced: 1989 Terminated: unknown 

Notes: 
Texas Instruments calls this an "Advanced scientific calculator". It is
keystroke programmable (although it lacks program flow control
instructions). Has complex number functions, a polynomial root finder,
alphanumeric entry, 440 memory steps dividable between program storage
and user memories. Can also perform calculations in binary, octal and
hexadecimal. Also available are statistical functions, temperature
conversions, and a (rather clumsy) way of repeating the last command
(dubbed "Last Equation Replay").
But what I find most striking is its keyboard, which lacks any kind of overview! Did anyone actually enjoy working with this calculator?

Picture: 
©2009 Ernst Mulder