X-Acto - Knife Blade - #11 Precision Z-Series Replacement Blades - PK of 100. Z Series No. 11 replacement blades are atomically sharpened and zirconium nitride coated. They stay sharp seven times longer than standard blades. They easily cut paper plastic balsa thin metal cloth film and acetate. Blades are designed for use in No. 1 precision knife and type A handle X Acto knives. • Blades are automatically sharpened and coated with zirconium nitride for a sharp durable blade. • Cuts through paper plastic balsa thin metal cloth film and acetate. Creates ultra-precise cuts. • Compatible with the Z-Series No. 1 precision knife and Type A Handle X-Acto knives. • Certifications standards- ACMI-AP. • Blade Size: #11. Atomically sharpened Z series #11 zirconium nitride coated fine point replacement blades are proven five times stronger particularly in the tips and stay sharp seven to 10 times longer than standard blades. • Sold as 100/Box.