We love lock-back utility knives. The problem is with the mechanisms that hold the blades when you're ready to replace them. You either need a separate tool to remove a holding screw or it has a flip-up clip that loses its holding power after a few blade changes. Our folding utility knife has a no-tool, spring-loaded lock that fits into the notch on the back of the blade. Just push down on the lever to remove the used blade or to put a new one in. Accepts standard utility blades including Irwin Bi-Metal Blades (190155).