I like messing around with gear that is very compact yet still functional.

One of the smallest functional whistles I've seen is the REI small keychain whistle. It gets so-so reviews since sometimes a batch of them is not made right. I also thought it better for a whistle to be plastic instead of metal, in case you use it in winter.

I saw one of those backpack sternum strap buckles with an integrated whistle and figured I could miniaturize it for a super compact kit.





I used a Dremel's cutting wheel and grinding wheel to remove the nonessential parts, leaving a tab for a 3/32" lanyard hole. The plastic is not brittle and it's easy to cut on. It worked out pretty well, and the whistle is darn loud. Not bad for about $2.

Great idea and nice execution.

Great idea! I think I may steal that one!

Wait, you write about those buckle whistles like they're a common thing!

Details, man! Price, and location. I'd buy a dozen and put them on every backpack I own.

I have a small metal whistle on my keyring -- tubular, 5cm long, cost about .50 on ebay.

they might just be.

my osprey stratos 40 has one on the sternum strap.

i didn't realize it was there until someone pointed it out.

Those are what I was looking for a while back. I already wrapped the kids packs so I'll have to wait until Christmas day to make sure the straps are 3/4"

Vey interesting. I'll check that idea out.

I've been wanting a tiny (or flat) whistle to put in my wallet, it may fit the bill.

Many thanks

With such a small size I'm guessing that the whistle is pretty high pitched. Is that true?

If so, what are the ramifications? Can older ears hear it well? What about penetration through vegetation?

I've been EDCing a Fox 40 Sonic Blast since Doug had mentioned them. I like it. Loud as heck and a decent form factor.

Aussie... TOPS Knives markets a flat 3 chamber whistle (about .3" thick), and I'm sure there are others... mine fits in multitool pouch, but would easily fit in a wallet