The small one has a spring, it's in the front of the mechanism instead of between the two pieces
the bigger ones don't have one at all
cheap stuff, is my guess, bought them at discount stores. Still, they do the job
My memory has had a delayed ping, my dad had Ford wrenches in his toolbox (USAF jet engine mechanic)
I wish I had it now, my dad's tools are my biggest regret of all the stuff we lost over the years after he retired and life went to hell
All I have left is his medals
he also had the german wrenches that inspired this knock off
http://www.amazon.com/Craftsman-CRAFTSMAN-CLENCH-WRENCH-00930879/dp/B008L2JUXCthe original, german ones he had, which sorta looked like mini pipe wrenches with a pivot instead of adjusters, NEVER failed to remove a bolt, unlike the craftsman version I have
probably we should knock off the thread jack
Sorry OP