This is a set of 3 each patented made in the USA, Easy Wood Tools Replacement Carbide Cutters designed for Full and Pro Size Roughers and Finishers and Micro Detailers . Set includes on each of the following: Ci0-NR, Ci1-R2-NR and Ci7-NR. Negative rake cutters work well on man-made acrylics, hard exotics and end grain producing a better finish, with less “grabs” and better edge life. Authentic EWT cutters have the optimal 3G's of Carbide - Grade, Grind, and Geometry. 1) The Right Grade: Carbide is basically a mixture of tungsten powder and cobalt that is fused together under high pressure and heat. The ratio of cobalt to tungsten and the size of the tungsten particles are referred to collectively as the ‘grade'. There are literally hundreds of thousands of conceivable grades and no ‘one grade' of carbide is suited for all applications – whether wood cutting or metal cutting. The perfect combination of cobalt and grain size in EWT carbide cutters yields a cutting edge that is both the keenest and the most durable grade for woodturning available today. 2) The Right Grind: EWT grinds all of their cutters on super rigid CNC grinders to prevent micro chipping of the cutting edges. EWT uses the proper grit diamond wheels to produce the flattest, truest surfaces possible with minimal grinding scratches left on the surface.  All the cutter surfaces are ground in the optimum sequence to bring the edge into keenness during the very last process, or once again micro chipping of the cutting edges will occur if the proper sequence is not followed. 3) The Right Geometry: EWT grinds all their cutters to the correct angles and geometries specifically for woodturning.  This produces an edge that cuts both cleanly and safely for all skill levels. Only when grade, grind, and geometry are in harmony will you have a cutting edge for high performance woodturning.