If they needed any additional credit to their name, I packed a couple Cobras I've got with rocky sand and dirt in an attempt to induce malfunctions. As with any mechanism, the action after packing it with debris was not as smooth as when it was clean, but both buckles, (an FC25B and an FC45SA-XL), remained in working order. Both still locked and unlocked fairly easily, sometimes requiring a slight tug to unlock fully. After locking and unlocking them a couple times, they freed up. This minor test was about a week ago and neither buckle has been cleaned yet. Neither shows ostensible signs of ever being mucked up and I feel that the FC25B is still professional-looking enough for daily wear on my belt.