When you buy Challenge SCM dies and knives for your SCM Hydraulic corner rounder online, you not only reduce any strain on your machine that may be caused from using a dull blade, you also guarantee a perfectly clean rounded corner for your paper and plastic materials. When combined with the SCM Manual corner rounder, these knives and dies can cut cleanly through a 2" thick stack of material. Made of premium materials for a long life, these SCM Manual dies come in a large variety of sizes including 1/8", 1/4", 3/8", 1/2", 5/8", straight and a 45° configurations. Because these knives and dies are not sold in a set, you only need to buy what you need to replace: so if your die is fine but your knife needs replacing, you only need to purchase a new knife; this way you are not spending money on unnecessary consumables before they are needed. However, both a die and a knife are required for the machine to work properly, so be sure that you have a full set before running your machine.