These dust caps and plugs are used to prevent foreign objects like dust, dirt and moisture from entering the Divator second stage, and intermediate hose.
Most users of the Divator FFM do not leave the mask attached to the intermediate hose when not in use. As a result, when the mask and hose are separated, moisture and other debris can easily enter the hose or second stage.
As can be seen in the picture, both the mask cap, and hose plug, have holes provided to attach a retention lanyard to help prevent loss.
The dust cap, and plug are manufactured from solid brass, and then protected with an “Electroless‐Nickel Plating”.