Help creating button list of available resolutions

OKay, I have a problem with this for :C . I'm trying to make few buttons with the resolution that the user can select, but I dont know why it dont works.

PLIS HELP!

 for (int i = 1; i < Screen.resolutions.Length;i++ )
 {
     if(GUI.Button( new Rect(400, 200 + (50 * i), Screen.width / 8, Screen.height / 10), Screen.resolutions[i].width + "X" + Screen.resolutions[i].height))
     {
         Screen.SetResolution(Screen.resolutions[x].width,Screen.resolutions[x].height,true);
     }
 }