It can be a hassle when trying to make a straight line cut on a wide plate, so this straight edge and roller guide makes the job easier. The cutter bar is a 1" rod, what ever length. The real addition is the roller guide that runs on the cutter bar. No more using both hands trying to hold the torch at the right height. I use a clamp on roller guide that will hold the cutting tip against the bar and at the right height. Great tool for old guys like me!!