the Fox 40 is a good whistle for people who need to get the attention of people real quick. it also is brillant in water and snow. the whistle dries very quickly and is quite loud. every now and then after it gets wet you should suck the water out of the whistle to get the maxium results out of it. I recomend the Fox 40 pearl or the Fox 40 Mini though.
This whistle is a life saver. Diving the Great Barrier Reef, was caught in a strong current off a shallow reef. Surfaced with dive partner & used the whistle to alert the dive boat to our location. Best [$] investment I've ever made.