CXG Sierra picture taken from the box front.
The CXG Sphinx Sierra is a beginners computer with few special features. It does however allow you to set up positions, play both sides and take back moves up to eight half-moves.
LEVELS OF PLAY
The operating key marked “LEVEL” - which can be used any time when it is your turn to move - enables you to alter the speed and strength of the computer’s play. When you press this key, the corresponding light on the control panel comes on, You can choose between sixty-four different “levels”. On level 1, the computer takes an average of 5 seconds per move. On higher level, it takes more time and its playing strength is correspondingly increased; the average for level 64 is 20-25 seconds per move.
Computers that have the same program as the CXG Sphinx Sierra are:
Excalibur's Model 638E Stiletto Deluxe is identical to CXG Sphinx Sierra in design and in game settings, features and play.
Some information taken out of the CXG Sierra User Manual.