I purchased this to give to my grandkids that are starting to fish. They are using it to practice tying the various knots and having fun. A good addition to the tackle box. A good reference tool for anone that wants to tie proper fishing knots.
It is water proof, small and convenient but there are some negatives. If you are new to fly fishing it does not tell you what purpose most the knots serve. Also as I have progressed I have learned several more valuable knots that it does not include.