Lutz heavy-duty retractable utility knives are designed to be reliable. Die cast from zinc for optimum strength and durability, they are built to last a lifetime. The Lutz #357 Quick Change Utility Knife comes in Hi-Vis Yellow and Blue. It has a specially designed holster for easy use. It's a heavy duty retractable utility knife designed for reliable and comfortable use. Excellent use for carpet and shingles due to its heavy duty premium quality. It has 3 heavy duty replacement blades stored inside the knife. We offer a Lifetime guarantee. The safety nose overlap on the top and bottom of the knife is a key safety feature, so the blade won't snap or pop out or back up on the user. The blade carrier has multiple raised posts to secure blades.