The Magafor 421 series cobalt steel single-end countersink with an uncoated (bright) finish creates a 90-degree conical opening that accepts a flat-head fastener so it sits flush with the surface. The single flute quickly cuts through material and has reduced vibration at higher speeds compared to multiple flutes. It is suitable for cutting small holes. Cobalt steel provides extended tool life compared to high-speed steel when cutting hard materials, and maintains the tool's toughness and hardness in high drilling temperatures. The uncoated finish has no additional surface treatment or coating. The tool has a single cutting end and a round shank that accommodates most drill chucks.

Countersinks are fluted cutting tools that cut a conical or gradually widened opening for a hole into the surface of a workpiece, which provides a seat for a screw or rivet head. They are also used to create center holes for a machine center, deburr surfaces, and enlarging existing holes. The countersink's body diameter should be the same size or larger than what is being countersunk.

Magafor manufactures precision cutting tools, including counterbores, countersinks, deburring tools, and end mills. The company, founded in 1937, is headquartered in Fontenay-sous-Bois, France.