Introducing the upgraded Greenlee Slug-Splitter S Knockout. Punch through stainless steel in less time and with less potential for errors or alignment problems. What's changed with the new knockout? If you're interested in making sure your holes are perfectly centered, we've added a self-centering feature. This new feature greatly simplifies conduit hole and pilot device alignment. Just tighten down the punch on your draw stud and let our new punch center itself on the pilot hole. No more trying to line up the die alignment marks in poor lighting conditions or drawing crosshairs on the box to ensure alignment. Greenlee has once again given you a tool designed to make your job easier.