Windows Low Level Disk Question

using( ManagementClass driveClass = new ManagementClass( "Win32_DiskDrive" ) )
{
    using( ManagementObjectCollection physicalDrives = driveClass.GetInstances( ) )
    {
        foreach( ManagementObject drive in physicalDrives )
        {
            string cylinders = ( string )drive["TotalCylinders"];
            // ... etc ...
            drive.Dispose( );
        }
    }
}