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Keystone 390

The Keystone 390 is an arithmetic calculator with 8 digits precision and algebraic logic. It has 5 functions, 20 keys and Discharge display. The power source is 4xAA sealed.

Facts at a glance:

Type Arithmetic
Functions 5
Keys 20
Precision 8
Logic Algebraic
Display type Discharge
Display size
Printer
Length 133 mm
Width 81 mm
Thickness unknown mm
Weight unknown g
Power Source 4xAA sealed
Country
Original price unknown
Est. current value unknown
Year introduced 1973
Year discontinued 1973

See other calculators manufactured by Keystone.