Think of your average Frame lock, or linerlock. It has a ball detent that keeps it in the closed position. Well thats basically what this system is. Inside both sides of the handle is a bar with a pair of Detent balls in them. Both of them pressing inward at the tang of the blade. With equal pressure. In the tang of the blade are detent holes which match up with the detent balls. So as the blade is rotated it meets these holes, at the Open, Midway and Closed position. Each set of holes is set to have a different amount of resistance. In the open position the holes create a complete block... so to provide the most solid joint as possible. Midway is just enough to keep the blade from closeing on your finger. And the closed has the least resistance... so to speak, which allows it to be opened without to much force... Very similar to the UKPK... In fact all of the spots are simliar to the UKPK, or Urban.