Fieldset and legend

<form class="mb-form">
  <fieldset class="mbl">
    <legend>Tracking type</legend>
    <div class="flex flex-wrap gcl grs">
      <label><input type="radio" name="tracking" value="rfid" />RFID tracking</label>
      <label><input type="radio" name="tracking" value="barcode" checked />Barcode tracking</label>
      <label><input type="radio" name="tracking" value="none" />Without tracking</label>
    </div>
  </fieldset>

  <fieldset>
    <legend>
      Container size
    </legend>
    <div class="flex flex-wrap gcs grm">
      <label>
        Height
        <input type="text" />
      </label>
      <label>
        Width
        <input type="text" />
      </label>
      <label>
        Length
        <input type="text" />
      </label>
    </div>
  </fieldset>
</form>