Literally. Being OCD about field litter, I picked up a bit of white trash that caught my eye (that for gutter minded) while doing some wet work (for the killer dillers and - and seriously gutter minded) on one of our leases the other day that turned out to be a long lost Haydel snow/blue call sharing a lanyard with what I gather is a Big River speck call some favor but I've never heard, a chromed metal dog whistle and a Primos duck whistle. All were packed with mud, and I pitched the snow call and dog whistle and nearly did the same with the Primos whistle, as I've tried a number of similar ones and long since settled on Haydel's MP-90.
Decided, instead, to soak the dirt out of the little Primos along with the Big River call I want to try and give it a toot. And danged if it isn't a better one, in terms of both ergonomics and sound, than what I thought the best of the litter. Is the smallest I've seen but as loud as any I've tried and smack dead on tone.
See they retail for $7 (http://www.primos.com/products/waterfowl-calls/duck-whistle-mallard-drake-grunt/, which is about $5 cheaper than the Haydel, too, so if I were looking to buy a duck whistle, this would be it. My Haydel's now in the "also ran" drawer.