Signal Mirror: A lightweight plastic mirror; most outdoors stores have them. Here's an example at REI.

Compass: Suunto clipper compass removed from watchband housing. Another example at REI.

Tweezers: Uncle Bill's Sliver Grippers (keychain model). Again, an example at REI.

Granted, I didn't buy all of this stuff at REI. Their prices can be a little steep, so take a look at an outdoor store near you, the items can be found a little cheaper.

The Witz box I am using is called the "See-It Safe" (clear model). They can be found on the Witz web site here.

As far as other items, I'm usually carrying a Leatherman product of some sort (new Wave, PST, or Squirt P4) and/or a folding knife (Benchmade, Spyderco) with me. Gave up trying to fit a knife in the Witz box and went with tweezers instead. Good for pulling out those ticks, thorns, and stingers! <img src="/images/graemlins/grin.gif" alt="" />

(p.s. - the whistle is about 0.31" thick)