After taking a quick glance, it would at first glance, appear that Gerber has standardized their folding tools in regards to the locking mechanism, be it an MP400, 600, right down to the Suspension style series. The indent looks the same for all tools. With that being said, I have no way of truly comparing them to see what works or what doesn't as I have no interest in modification. So you might want to hear from someone who is more knowledgeable on the matter at hand.