I'm by no means an expert of scribbing, but its a thick rigid tape that helps you to cut in straight lines. This is mostly used for creating new panel lines, but it also helps to scribe the existing ones too. So, you tape the edge of whatever you want to scribe and run your knife along side it. The tape will keep the knife from jumping out of the line. I used the Dspiae one, but they're all the same no matter who makes them.