This is our DoubleDon Welt system that I believe it is unique to us. Many high-end heavy duty boots have a storm welt construction, this is similar however it is double soled, and has been handled twice. It's a look that is special with an extra ridge to the sole edge. for me its almost looks like a staircase at the side of the boot. So if you are after something completely different, why don't you try our double don Boot.