For good reasons we already all know, Doug suggests we add a first aid kit, a key-chain LED flashlight, a pocket-sized personal shelter, a decent knife, at least 1L of water (in a Nalgene bottle for instance) and Katadyn MP1 tabs (the only one that kills cryptosporidium cysts), matches and striker and something in which to store and treat the water like two condoms or your Nalgene bottle for instance.

I compared it to Doug's original PSK and I found that there are two items missing:

1. A survival wire saw. But Chris already pointed out "[...] The classic wire saw and button compass were developed for downed british pilots. The saw was actually meant to be used on seasoned fences and not so much on resin filled living trees. There are surgical wire bone saws available. I played with a few, thinking a saw meant for living tissue would perform better. The result produced no discernable difference. [...]
And I personally don't think it's critical.

2. 11in. Teflon tube for water seeps. This one looks interesting to me and shouldn't take up much space. Where do you find those tubes? In a medical supplies store? And what's the ideal diameter?

Thank you
Frankie