SINCLAIR CAMBRIDGE CALCULATOR 
TYPE 3 MODEL DATING FROM BETWEEN 1973-1975.
 

8 DIGITS, RED LED DISPLAY.
4 FUNCTIONS AND K (CONSTANT) BUTTON.
C/CE BUTTON. (ONE PRESS CLEARS LAST ENTRY, TWO PRESSES CLEARS EVERYTHING).
MAIN INTEGRATED CIRCUIT: GENERAL INSTRUMENTS MICROELECTRONICS.

6V (4 x AAA).
50 mm x 111 mm x 28 mm (2" x 4.4" x 1.1").
MADE IN ENGLAND.