DMT DIA-FLAT Lapping Plate Precision ground and hand-certified flat to &lt;+/- 0.0005-Inch Aggressive surface to facilitate quick and easy flattening of conventional and Arkansas stones and waterstones DMT Diamond Hardcoat Technology outlasts any other diamond coating on the market Largest surface area of any diamond lapping plate - 40 square inches or 50% larger that other diamond lapping plates Durable construction will provide years of consistent performance and reliable service. Made in USA