Abstract: A knife comprises three main parts: a handle, a blade and a removable spring lock guard. The handle, formed of two spaced apart lateral handle halves includes a blade pivot adjacent its forward end. The blade, configured as a double-ended, double-edged single blade, is mounted intermediate its ends to the blade pivot for rotation to positions in which one of its ends is contained within a slot provided between the handle halves while its opposite end extends forwardly of the handle for use. A spring lock guard is configured to releasably overlie the slot in the handle and confine the inoperative blade, thereby securely locking the single blade against inadvertent rotation during use.