<div class="form-group col-md-1">
    <label class="quantity_label">Quantity: </label>
</div>

<div class="form-group col-md-3 quantity_input">
    <div class="input-group">
        <span class="input-group-btn">
            <button type="button" class="btn btn-default btn-number" disabled="disabled" data-type="minus" data-field="lan_quantity">
                <span class="glyphicon glyphicon-minus"></span>
            </button>
        </span>

        <input type="text" id="second_lan" name="lan_quantity" class="form-control input-number price-select" value="1" min="1" max="48">

        <span class="input-group-btn">
            <button type="button" class="btn btn-default btn-number" data-type="plus" data-field="lan_quantity">
                <span class="glyphicon glyphicon-plus"></span>
            </button>
        </span>
    </div>
</div>

<div class="form-group col-md-12">
    <label for="old_hl_number">Serial Number (16 digits) *</label>
    <input type="text" name="old_hl_number" class="form-control" id="old_hl_number" required>
    <div id="old_hl_number-error"></div>
    <div id="wrong_hl_num-error"></div>
</div>