Download this step-by-step ‘walk-through’ to aid with the inspection and maintenance of DMM (and other) auto-lock carabiner gate mechanisms.
Following on from a visual and tactile assessment, there are three gate action (function) tests described, to ensure that the gate closes fully and reliably. A non-silicone based lubricant such as Duck Oil is recommended (do NOT use graphite powder) to reduce friction at the hinge rivet, within the mechanism and contact areas.
As always, if you have any doubts about the functionality or integrity of a carabiner, take it out of service and seek advice. A downloadable PDF of this guide is available by clicking directly on the image below.