Ah, the Fox 40 Micro is the whistle that Doug packs in his PSP kits.
http://www.countycomm.com sells them in orange or black - with a lanyard - for $5 each.
And their made in Canada eh?! (no, I'm not from Canada, but I'd rather support our good neighbor than countries in the far east)
I still would rather carry the Storm - it is deafeningly loud.
By the way, for those that carry the regular Fox 40, have you seen that you can shave down the belly of the whistle's body without affecting its characteristics? The rounded body is just there for looks & grip. It has no real function. That reduces the thickness to about 18 mm. Doug describes that at
http://www.equipped.org/pp/pic691.htm .
By the way, that's some really nice photography Doug!! I know Terril Hoffman does Doug's knife photography for him - maybe he did this one too. Terril is gifted!