<nav id="main-menu">
  <div class="wrap-slider">
    <ul class="menu vertical medium-horizontal" data-auto-height="true" data-responsive-menu="dropdown medium-dropdown">
      <?php wp_nav_menu( array(
          'container' => '',
          'menu' => 'main-menu',
          'theme_location' => 'main-menu',
          'items_wrap' => '%3$s'
        )
      ); ?>
    </ul>
  </div>
</nav>