Tippet is the thin clear fishing line that goes between your main tenkara line (which is necessary for casting) and your fly. This is standard fly-fishing tippet, which can be used for tenkara and fly-fishing in general. 5X, which is equivalent to roughly 5lb (2.5kg) test strength is the recommended rating of tippet for tenkara. This allows you to break off the tippet if caught in deep snags or high trees, with a lower chance of breaking the rod.