1. Display: LCD, 2 line(s) X 10 characters (minimum), stably shows input-expressions/equation, calculation result, and various indicators;
2. Built-in functions not less than 240 inclusion of the following:
A) Basic Calculations: Arithmetic, fraction, percentage, degrees, minutes, seconds, radian (including conversion of the mentioned Basic Calculations);
B) Memory calculation, Logarithm and Hyperbolic functions;
C) Statistical functions (e. G.: Statistical relationships, standard deviation, Permutation, Combination, etc. ); And
D) Trigonometric functions: Sin, cos, tan, sin-1, cos-1, tan-1;
3. Basic keys and function keys are labeled permanently (resistant to finger
Rub and light acid (vinegar) contamination) and operates as such correspondingly;
4. Power requirement: Two way dual (battery, built-in solar system), the unit consistently operational after replacing the battery for three trials, its solar system powers the unit normally in a well lit room without the battery;
5. Brand must be established in providing quality products for 5 years and up.