Multiple material select

<div class="col-md-6">
    <div class="md-form">
        <select id="select" class="mdb-select grey-text" multiple>
            <option value="" disabled selected>Select Facilities To Visit</option>
            <option value="1">Chiller Rooms</option>
            <option value="2">Battery Room 1</option>
            <option value="3">Battery Room 2</option>
            <option value="4">UPS Room 1</option>
            <option value="4">UPS Room 2</option>
            <option value="4">UPS Room 3</option>
            <option value="4">UPS Room 4</option>
            <option value="4">UPS Room 5 (Chiller Rooms)</option>
            <option value="4">Entrance Room 1</option>
            <option value="4">Gas Room</option>
            <option value="4">Telecoms Room</option>
            <option value="4">High Voltage</option>
            <option value="4">Low Voltage</option>
            <option value="4">NOS</option>
            <option value="4">MDA Room</option>
            <option value="4">F1</option>
            <option value="4">F2</option>
            <option value="4">F3</option>
            <option value="4">F4</option>
        </select>
        <label for="select"></label>
    </div>
</div>

<script>
    // Material Select Initialization
    $(document).ready(function() {
        $('.mdb-select').material_select();
    });
</script>