The Kony utility knife is built around a hardened SK5 high-carbon steel blade that scores into eight segments. When one section dulls, snap it off and a fresh edge is ready in seconds.
The body is machined aluminium wrapped in a rubber grip, so it survives being dropped off a ladder and stays under control when your hands are dusty or gloved. A three-position slider locks the blade where you want it and pulls it fully back into the housing when you are done.
Two details separate it from a supermarket box cutter: an inch ruler running the length of the body, and a recessed bubble level. Mark a straight line and check it is level without reaching for another tool.