The Wiss Auto-Retracting Safety Utility Knife has a ergonomic design with a quick blade change system for ease of use. The blade retracts automatically the moment it loses contact with the material being cut, even if the user is still holding the blade slider forward in the 'open’ position. This helps reduce workplace injuries, lowering lost time and increasing productivity Accepts all standard type utility knife blades and includes 3 black coated blades.