The learning aid TRIGONIR© is patented (© S. Čičak). Trigonir© is a product of a long lasting career in education. Teachers of mathematics have long been searching for a way to present trigonometric functions to students in an easy to understand yet professional manner, since the expression sine alone tends to evoke a feeling of discomfort among quite a few students. This learning aid is the result of this consideration and has already been tested in various schools in Europe. Trigonir© brings forth a new, creative and interesting approach to analyzing and using trigonometric functions, which renders them understandable to all students, including those, who are not very fond of mathematics. Trigonir© is comprised of two planes that are connected and movable. The bottom plane has the unit circle, angles from 0° to 360°, the tangent and cotangent axis as well as the values of trigonometric functions for basic angles inscribed on it. Red color is used to emphasize the negative values of trigonometric functions. The upper plane has only one axle inscribed on it and can be moved circularly in order to determine various attributes of trigonometric functions for various angles. Trigonir© enables us to determine the following properties of trigonometric functions: - domain and co domain of functions, - zeros of functions, - points where a function is not defined , - increasing and decreasing of the function, - positive/negative values, - periodicity, - evenness and oddness of a function, - accurate value of basic angles, and - properties of inverse functions (arcsin α, arccos α , arctan α , arccot α). The objectives of the learning aid Trigonir© are: - less time spent on handling trigonometric functions, - a more interesting presentation of the subject, - a more active involvement of students during lessons, and - making studying easier and more independent.