NT professional quality 30-degree snap-off black blades for standard duty utility knives are perfect for various precision works. These extra sharp 30 degree blades are made of high quality carbon tool steel and produced through multiple stages of precise process to obtain the ultimate sharpness and optimum edge-retention. The process includes a unique “Bluing process” which adds an oxide coating on the blade and gives it a blue-black appearance and protects it from rusting. The final vigorous step is a sharpening process called “lapping”, which completes the cutting edge processing of these professional blades to achieve the maximum sharpness. Through these special procedures, NT created the flawless, rust-resistant precision blades that can effortlessly cut papers without tearing or dragging. Blades are so sharp that cutting lines are almost virtually invisible. Recommended for professional use, due to its fine delicate edge. Made in Japan.