Nakiyo Double Diamond Butterfly Sharpener

Butterfly knives may be illegal in Washington, but butterfly knife sharpeners aren't! The Nakiyo Double Diamond Butterfly Sharpener features two diamond plates at 360 and 600 grit to put a coarse but effective edge on a pocket or outdoor knife, all housed inside two counter-rotating ABS handles so that it doubles as a practice balisong. The four screws can be loosened or tightened to adjust the play.

To use, hold the knife steady and firmly stroke the sharpener along the length of the blade at approximately a 20° angle. Start with 360 (extra coarse) and finish with 600 (coarse).

This sharpener is recommended for pocket and outdoor knives only. For kitchen knives, sharpening stones are ideal, but other, easier sharpening tools are also available.