<!-- Large -->
  <div class="btn-group">
    <button class="btn btn-default btn-lg dropdown-toggle" data-toggle="dropdown">Large <i class="fa fa-caret-down"></i></button>
    <ul class="dropdown-menu" role="menu">
      <li><a href="#" tabindex="-1">Action</a></li>
      <li><a href="#" tabindex="-1">Action Two</a></li>
    </ul>
  </div>

  <!-- Default -->
  <div class="btn-group">
    <button class="btn btn-default dropdown-toggle" data-toggle="dropdown">Default <i class="fa fa-caret-down"></i></button>
    <ul class="dropdown-menu" role="menu">
      <li><a href="" tabindex="-1">Action</a></li>
      <li><a href="" tabindex="-1">Action Two</a></li>
    </ul>
  </div>

  <!-- Small -->
  <div class="btn-group">
    <button class="btn btn-default btn-sm dropdown-toggle" data-toggle="dropdown">Small <i class="fa fa-caret-down"></i></button>
    <ul class="dropdown-menu" role="menu">
      <li><a href="" tabindex="-1">Action</a></li>
      <li><a href="" tabindex="-1">Action Two</a></li>
    </ul>
  </div>

  <!-- Mini -->
  <div class="btn-group">
    <button class="btn btn-default btn-xs  dropdown-toggle" data-toggle="dropdown">Mini <i class="fa fa-caret-down"></i></button>
    <ul class="dropdown-menu" role="menu">
      <li><a href="" tabindex="-1">Action</a></li>
      <li><a href="" tabindex="-1">Action Two</a></li>
    </ul>
  </div>