<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<form class="form-horizontal">
<fieldset>
<legend>Cylinders installation design</legend>
<div class="panel panel-default">
<div class="panel-heading">Products</div>
<div class="panel-body">
<table class="table">
<thead>
<tr>
<th>Unit</th>
<th>Product 1</th>
<th>Product 2</th>
<th>Product 3</th>
</tr>
</thead>
<tbody>
<tr>
<th scope="row">Gas</th>
<td>
<select id="gas" name="gas" class="form-control">
<option value="1">Oxygen</option>
<option value="2">Argon</option>
<option value="">Carbon dioxyde</option>
<option value="">Hydrogen</option>
<option value="">Flamel</option>
<option value="">Ammoniac</option>
<option value="">N/A</option>
</select>
