optional, single

ref=unique identifier of the breathing gas to be cross-referenced

<switchmix/> indicates the breathing gas used. It's possible to change the breathing gas during a dive as often as necessary, but only one <switchmix/> statement may occur inside a <waypoint> element.

The first <waypoint> of a dive profile must contain a <switchmix/> statement — to indicate the breathing gas used during this dive (or at least to determine the starting breathing gas).

<waypoint>

—

<waypoint>

(see also <waypoint> e.g.)

<samples>
    <!-- the first waypoint of a profile -->
    <waypoint>
        <depth>0.0</depth>
        <divetime>0.0</divetime>
        <switchmix ref="air"/>
    </waypoint>
    <!-- here follow many other waypoints -->
</samples>