The Emerson Wave Shaped Feature is a fast, effective, and impressive way to open your knife. The patented opening method is a small wave-shaped tab on the top of the blade that's built to catch on your pocket seam, opening the knife as you withdraw it from your pocket. This instant-open feature is a favorite among military, rescue, and law enforcement knife users. But it does take a little practice. This trainer, with an unsharpened blade, is the tool you need to get that practice.