Save Matrix 4x4?

Hi Guys!

I need help as fast as possible. I tell them that I am developing a game with an accelerometer. And the subject of calibration, it is going crazy. I give them the Script of movement that I am using:

     //Method for calibration 
     public void calibrateAccelerometer()
     {
         wantedDeadZone = Input.acceleration;
         Quaternion rotateQuaternion = Quaternion.FromToRotation(new Vector3(0f, 0f, -1f), wantedDeadZone);
         //create identity matrix ... rotate our matrix to match up with down vec
         Matrix4x4 matrix = Matrix4x4.TRS(Vector3.zero, rotateQuaternion, new Vector3(1f, 1f, 1f));
         //get the inverse of the matrix
         calibrationMatrix = matrix.inverse;
     }
 
     //Method to get the calibrated input 
     Vector3 getAccelerometer(Vector3 accelerator){
         Vector3 accel = this.calibrationMatrix.MultiplyVector(accelerator);
         return accel;
     }
 
     //Finally how you get the accelerometer input
     Vector3 _InputDir;
 
     // Use this for initialization
     void Start () {
         
 
     }
 
     // Update is called once per frame
     void Update () {
         _InputDir = getAccelerometer(Input.acceleration);
         //then in your code you use _InputDir instead of Input.acceleration for example 
         //transform.Translate (_InputDir.x, 0, -_InputDir.z);
         MovimientoAcelerometro ();
     }

Simple, need save CalibrationMatrix (Matrix4x4) WITH A BUTTON AND LOAD AUTOCALLY IN VOID START ALLWAYS PREVIOUSLY SAVED.

CAN SAVE MATRIX4x4 WITH PLAYERPREFS??? NEED HELP.

THANKS YOU FOREVER! Sorry for my english =D