The Faber-Castell TR4 is a scientific calculator with 8 digits precision and algebraic logic. It has 26 functions, 25 keys, and an LED (light-emitting diode) display, typical of calculators of this era. Note: Combination slide rule and calculator.
Facts at a glance:
If you have a Faber-Castell TR4 that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement: