Fully Retractable Knife Features A Safe, Retractable No. 11 Blade. Easily Change The Blade As You Would With Any X-Acto No. 11 Blade. The Knife Is Perfect For Delicate, Precision Cutting And Trimming Of Lightweight Materials, Such As Paper, Plastic, Balsa, Thin Metal, Cloth And Film. The Soft, Triangle-Shaped Comfort Grip Provides Extra Control. Anti-Roll Handle Keeps The Knife From Rolling Off Your Worksurface. Retractable Knife Also Offers A Metal Core Construction For Durability.