Depending on where the OP is located and how many kits he and the scout troop are planning to build, I have a collection of Fox 40 whistles (courtesy of my local .gov) I can donate.

The OP can PM me with the details.
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Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters, and teach some of us more than we can ever learn from books.

John Lubbock