Designed to fit on Infinity Tools Insert-Pro Raised Panel Shaper Cutter Heads for cabinet doors, these solid carbide knives are made from a C4 sub-micron grade of carbide that will last longer and outperform any brazed carbide cutters on the market. You will not believe the mirror finish we are able to put on these knives and how sharp the edges are. The quality of cut they produce is superb and sharpening is very simple. We recommend you keep a fresh set of knives on hand to eliminate down-time.