I think their great. I used mine to propose to my wife. I enclosed a pirates treasure map that led to her ring. Strategicaly buried it on the beach in Hawaii and played it off like the discovery and the quest was all by chance[;)].
Wish I could say I did dive. Actually, my mom found this bottle while diving, in the early 60's. She actually held the worlds record for catching the largest octopus, free hand. Only lasted for about six months but she was proud of it.
Anywhoo, the bottle is one of many. It just happens to be...