We are manufacturing this tool with a special diamond coating process which results in longer tool life than the electro-plated brazing method. Diamond grit size is D427 (μm) / 40# (Mesh). Used in the boat and RV industry to trim laminated fiberglass boards. Cuts fast and clean. Excellent for Cutting: Fiberglass Fiberglass PCB Board Carbon Fiber Carbon Fiber Reinforced Polymer (CFRP) Composites Metal Matrix Compsoites (MMC) Micarta® (Brand name for composites of linen, canvas, paper, fiberglass, carbon fiber or other fabric in a thermosetting plastic.) Thermoset Composites Thermosetting Plastics