Lizard® Safety Utility Knife SC-6012
https://safecutters.com/crewsafe-lizard-safety-utility-knife-sc-6012/
The Lizard Safety Knife (SC-6012) is designed to prevent cuts and lacerations. The Lizard’s patented design has a retractable blade cover that locks safely back into place after cutting, leaving no loose or exposed blades. The blade of the Lizard is permanently imbedded in the handle of the knife so when the blade dulls, simply dispose of the entire Lizard knife. There is never any need to touch or change the blade.