Tiffany and Co has a nice silver whistle keychain for $85, if you take the keychain part off it and put it on a nice silver chain it can be worn around the neck. It seems like a good gift for a child or wife who wouldn't normally carry a whistle. It is high pitched like a dog whistle and is pretty loud, it is also easy to blow. It isn't a Fox 40, but it is a lot better then nothing. Plus I think because of its high pitch a SaR dog should be able to find it from quite a distance if trained to look for it. Just a little something I thought you guys would like.

Here is the link:
Piccaso designed keychain whistle