FrogPad

FrogPad is a small chorded keyboard about the size of a numeric keypad that can be used with one hand. It was produced by Frogpad Inc.

The keyboard is optimized by character frequency. 85% of average keystrokes in English text can be typed without chording, and chords are limited to 2 fingers (opposable thumb and one finger). As a result, the FrogPad has many more keys than a GKOS or Microwriter or Baudot keyboard but fewer than a conventional computer keyboard.