Funny story about those 511 pants...
About a dozen years ago I wore a green one frequently when hunting. One day I climbed up a tree to scan an overgrown pasture. I climbed up pretty high and on my way down I slipped and stopped when that back strap above the rear pocket caught a broken limb. I had some support on one feet and other feet was just dangling...riding the pants way up my waist and causing a lot of stress on my crotch. I struggled for about 10 minutes trying to get some support on both feet so I could lift myself high enough to free the strap from the branch. I ended up cutting the strap with my knife to get down.