There are the case, keypad and a digital display (a timer). Players should enter a correct code (1-30 digits). If they do this, they will stop the timer and hear a triumphal music. If not, they will hear the sound of a siren.The device works only when the case is opened. 8 AA batteries are used in this prop. There is a service code to change the correct code and time for the game. A micro SD card is installed in the fake bomb. Therefore, you can change the mp3 files.