Have you ever been on the water, rain coming down and you just can't remember if that knot is over then under and through or the other way around?  We've all been there but it isn't always convient to dig out your phone, hope there is coverage and then look up that knot.
 
These simple waterproof cards have the basics covered.  The core basic knots you need and other handy info when you need to up your fishing game for tricky fish.