UltraMax ultra-sharp premium standard-duty snap-off black blades, exclusively designed for maximum cutting performance, are ideal for applications where superior sharpness is required. These blades made from high quality carbon tool steel are developed using a "special" double honing process for extreme sharpness and are 25% sharper than our Standard-Duty AB blades. Long lasting durable snap-off blade - a new sharp edge with each snap. Blade container locks for safety. Fits most Standard -Duty handles. 13 cutting edges per blade. 10 blades per pack.