Loon Apex Hook Hone XL

Full Product Description (From the manufacturer)

The best way to sharpen big flies. Big fish don't come with big margins for error, and it's heart breaking to miss the fish of the trip because you were slow on the trigger your knots, or neglected to sharpen your hook. The Apex Hook Hone is sized to make quick work of sharpening big flies and doubles as a knot-tensioning tool so that you can take advantage of any opportunity you get at feeding fish.