No. 1 Z-Series Precision Utility Knife with Replaceable Steel Blade, Safety Cap, Silver, X-Acto, Mfr#: XZ3601W

Our sharpest and most durable #11 blade ever. The gold hue on the cutting edge is a zirconium nitride coating applied at the atomic level after blades are atomically sharpened. The coating on the blades adds significant strength to the blade itself, particularly the tip.