add_action( 'rwmb_meta_boxes', function( $meta_boxes ) {
$meta_boxes[] = array(
    'title' => 'Directory',
    'type'  => 'user', // Specifically for user
    'fields' => array(
        array(
            'name' => 'Which directory',
            'id'   => 'Which',
            'type' => 'checkbox_list',
             'options' => array(
                'public' => 'public',
                'members' => 'members only'
            ),
        ),
    ),
);

$meta_boxes[] = array(
    'title' => 'location',
    'type'  => 'user', // Specifically for user
'fields' => array(
   array(
            'name' => 'Location',
            'id'   => '7',
            'type' => 'checkbox_list',
             'options' => array(
                'brisbane' => 'brisbane',
                'melbourne'   => 'melbourne',
                'sydney' => 'sydney',
                'adelaide'   => 'adelaide'
        ),
      ),
    ),
);

$meta_boxes[] = array(
    'title' => 'Speciality',
    'type'  => 'user', // Specifically for user
'fields' => array(
   array(
            'name' => 'Speciality',
            'id'   => 'Speciality',
            'type' => 'checkbox_list',
             'options' => array(
                'bridges' => 'bridges',
                'roads'   => 'roads',
                'high rises' => 'high rises'
             ),
      ),
    ),
);

  $meta_boxes[] = array(
    'title' => 'Membership type',
    'type'  => 'user', // Specifically for user
'fields' => array(
   array(
            'name' => 'Membership type',
            'id'   => 'Membership_type',
            'type' => 'select_advanced',
             'options' => array(
                'contractor' => 'contractor',
                'associate'   => 'associate'
             ),
      ),
    ),
);

return $meta_boxes;
} );