Lastly, you will insert your IMU board into the IMU case and secure it with 4 of the small black, self tapping screws. Close the IMU with the included IMU Lid and 4 of the small black, self tapping screws. Please note that not all IMU boards will fit our IMU mounting case. It was designed for 23mm x 23mm square IMU boards. You might need to modify the IMU case to make your IMU board fit.