. . It locks into place by hooking into a plastic slot. So when you want to secure it, insert the slot into the hole and pull until it clicks. When you want to let go, squeeze both sides together to let go. It seems secure and works, but I have two complaints about this belt, although it will become my everyday belt that I wear to work: My first complaint is that the buckle is plastic. A metal buckle would have been better. My second and final complaint is that the portion of the buckle clip that goes through the loops on your belt is wider than the loops, requiring you to thread the ends through each loop. It adds about 30 seconds to my morning routine just to put the belt on. Not a big deal, but I think it's worth mentioning. Otherwise I like the style of the belt, I just wish the buckle was metal and the end that goes through the loops was a bit narrower so I don't have to fiddle with each loop to get it through.