3 Blades...specifically positioned to extend gradually closer to your beard, to shave you progressively closer in a single stroke. So close there is less need to reshave, which means less irritation. Patented DLC (tm) comfort edges...each blade has a patented DLC comfort edge, so Mach3 glides effortlessly and comfortably across your face. All Mach3 cartridges fit all Mach3, Turbo, Power, Venus, Devine handles.