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Keystone 350 (Berkey Keystone)

The Keystone 350 is an arithmetic calculator with algebraic logic. It has 5 functions, 18 keys, and a gas discharge display.

Facts at a glance:

FeatureValue
TypeArithmetic
Functions5
Keys18
LogicAlgebraic
Display typeDischarge
Year introduced1975

Replacements:

If you have a Keystone 350 that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current models as possible replacements:

See other calculators by Keystone