Sterling Sharpeners Knife Sharpener Blue STSBK. This knife sharpener manufactured by the experts at Sterling Sharpeners features tungsten carbide blades and can be carried on your keychain in your pocket or tackle box. Specifications for Sterling Sharpeners Knife Sharpener: Manufacturer: Sterling Sharpeners Overall Length: 3 in Package Contents: Sterling Sharpeners Knife Sharpener Keychain Sterling Sharpeners STSBK: Knife Sharpener Blue