  We experimentally test the universality of the Anderson three dimensional
metal-insulator transition. Nine sets of parameters controlling the microscopic
details of this second order phase transition have been tested. The
corresponding critical exponents are independent (within $2\sigma$) of these
microscopic details, and the average value $1.63\pm0.05$ is in very good
agreement with the numerically predicted value, $\nu = 1.58$.
