Professional Bule Nano nAco Coating - 2.5X Longer Life Compared to Uncoated Bits Blue nano nAco coating Series Router Bits utilizes a special unique carbide with composite coating for a longer lifetime (up to 2.5X longer life compared to uncoated bits) in modern materials. Nano blue coating enables the tool's cutting edge to retain crucial sharpness and lubricity. This provides longevity and produces cutting results of the highest quality. Coating prevents high heat and oxidation which is detrimental to cutting tool performance.