To the need for démonstraction physyque or educative, it is exellent and robust to chocks. For an object that resists in its operation a bit longer, and with a finish Mechanical slightly more refined, to execute reliefs measurenments few amelieurents would be indispensable. Conclusion: It was worth what we spent and benefit; the one who buys to see its use. I can not despise the object because there Gyroscopes course touts the points of view, but then it takes to spend a small fortune.