optional, multiple

id=unique identifier for this oxygen sensor

<rebreather>

<aliasname>, <manufacturer>, <model>, <name>, <nextservicedate>, <notes>, <purchase>, <serialnumber>, <serviceinterval>

<equipment>

(see also <rebreather>)

<o2sensor id="sensor_o2_1">
    <manufacturer>O2-Sensor-Guru</manufacturer>
    <model>O2-Extremely-Precise</model>
    <serialnumber>162534</serialnumber>
    <purchase>
        <datetime>2015-04-03</datetime>
        <shop>The Dive Professional</shop>
    </purchase>
</o2sensor>