Are survival cards, such as the following, any good? The following appears to have a better design than some of the others I have seen, though there may be better.

This company also has what seems like an interesting product, a tiny knife sharpener. Does anyone know if it is any good?

Jeanette Isabelle
"I have no quarrel with you, good sir knight, but I must cross this bridge." Arthur, Monty Python and the Holy Grail