I've just freed up a little space in a couple of my PSKs by switching from the (small) flat plastic ACR whistle to some I spotted at REI- in amongst the brighly-anodized key-chain novelty section that seems to exist in all outdoors stores now, there's a new (at least, I hadn't seen it before) smaller whistle that's just teensy... it looks like a scaled-down version of the one I've seen for years, but this one is just over a quarter-inch in diameter (pencil diameter) and less than two inches long.

It's shrill but single-toned, hence not as attention-getting as others, so I'll probably keep the ACR in my "boating" PSK. Still, it has to be the loudest whistle for it's size- perhaps because it's the only one I've seen it's size. When dealing with the cramped confines of an Altoids-size tin, any little bit helps. $3.

Tiny REI whistle

Yup.

I've got a few identical whistles sold under the brand name of Omega-Pacific.

I like one in my Altoid kit for the same reason. I also carry one on my keychain, as I have so much other stuff on there that a larger whistle just adds to the cluster.

If I'm going to be in the outdoors, then of course I opt for something louder like a Storm.

Harley

Those are exactly the same ones I use in my Altoids tins, though they're not brand labeled. Can't beat 'em for the size and the price!

Looks a lot like what www.bisonbelts.com sells. I think that their's go for $1.50 each. I should receive my order from them this week.

I just hope you don't need it in really cold weather.

I prefer plastic. It is lighted and I don't like things that can freeze to my lips.

I agree and that's why I didn't buy those tiny metallic whistle (my local camping store have two or three models).
I prefered to add ACME 2000 plastic whistles (sawed off to gain space) to my kits.

OTOH, if metallic whistles are kept inside clothes, they should not be too cold....

Thanks a bunch for the tip! I've been looking for whistles just like these. I'll be placing an order shortly.

Speaking of tiny whistles, I am always looking for tiny, keychain-size tools and gadgets that will easily fit on one's keychain (or in one's coat or trouser pockets). These should be functional but not attention getting. Anyone here use / have / own other tiny tools they'd like to talk about?

try a search on keychain or mega-keychain in the forum. Remember to set the date range to all dates or you wil only get the last week or so. There have been many threads on keychain stuff.

Thank you. I will.