This is the most useful fishing tool I own. It looks to me like Hardy has changed supplier since I bought my combo tool. It's still made from stainless steel, but these feel slightly rougher and less well finished than my old set. However, all the tools work in exactly the same way.

Four tools in the combo: snips, knot tyer, hook hone and hook-eye clearing needle. Of those, for me, the key tools are snips and knotting tool. The needle is handy but rarely used, I don't think I've ever used the hook hone. By contrast, the snips are used every time I knot monofilament, the nail-knotting tool is used every time I attach a fly line to backing and just about every time I attach a leader to a fly line.

I doubt any angler needs me to tell them how to use snips, needle or hook hone. Using the knotting tool efficiently takes a little practice and, unfortunately, no instructions are included with the Hardy tool.

For a simple nail-knot one line wraps and knots around the other, usually the thinner line around the fatter. Lay the thinner line over the bridge and hold it in place on the bridge with your thumb. Take the free end through the notch at the tip, I need a few inches of line to make the knot. Wrap the line around the tool four or five times, touching turns are nice, wrapping away from the tip. Thread the free end under the wraps towards the tip. From the tip of the tool, feed the thicker line under the wraps (I usually take that line over the bridge so I can hold it in place.) Gently, either pull the free end of the thinner line or slide the wraps off the tool onto the fatter line. Again gently, pull the ends of the thinner line to tighten the wraps around the fatter line and trim the ends of both lines.

(Word of caution: For most fly lines this simple knot works extremely well. However, a nail-knot tied this way can cut into the coating of a fly line and if the core of the line is slippery, e.g. if the core is monofilament, used in clear fly lines, the knot can strip the coating and slip off.)