There are 12 models in this series, including 10 regular models , 1 surprises model and 1 secret model. The probability of getting a regular model is about 9.31%, the probability of getting a surprise model is about 5.56%,and the probability of getting a secret model is about1.38%. That is, there will be 4 surprise models randomly replacing 4 regular models in every 72 models, there will be 1 secret model randomly replacing 1 regular model.
