Sinclair Executive Calculator
Manufacturer: Sinclair Radionics, LTD
Dimensions: 56mm x 138mm x 9mm / 2.2″ x 5.5″ x 0.4″
Made in: England
The Executive was the first Sinclair calculator, launched in the summer of 1972. It was very thin for the time due to the innovation of using button cell batteries to power the unit.