Yeah, i dunno which one is my toughest or most durable.... Probably my field knife. It was made by Bryan Breeden (awesome dude - former custom knife maker) as a gift to me for "services rendered behind 'enemy' lines" (not in the US gov't employ.... inside joke).
The knife is 11" OAL - 6" blade/5" handle. It's just a hair over 2" wide at its widest and made from 1/4" O1 tool steel w/Bryan's heat treat (which is freakin' awesome). The knife came unbelievably hair poppin' sharp - think something like an obsidian scalpel. My sharpening skills are not nearly what Bryan could do, but it i keep it such that it easily 1-pass shaves.
So, if you're an armchair "operator" you may not like my sharpened pry bar. However, when i went through my companies SERE training (my Plt. Sgt was a SERE instructor so we trained on SERE stuff regularly), i wish i had had a knife like the one i designed and Bryan made for me.
So here she is in all her unsparkling glory (dead standing oak tree was cross-batoned NOT chopped down):
And another pic as Bryan is holding her (brand spankin' new):
I've made a leather sheath for it, but do not have any good pics of it...
ETA: some stuff