There's a spot for your hydration of choice, your GORP, your compass, your firstaid kit, and you could even tie a longsleeve throught the lock holster if you wanted to. So much less sweaty than a backpack (we did a side-by-side comparison and it was pretty much a landslide victory). And may this be a public service announcement for your local underutilized national and regional parks: Go to them! They are beautiful and it is October! You won't be sorry.
