The unlocking and locking system is the feature I prize. For the user whose hand does not have the strength to open the ring of the ordinary binder this special binder is the answer.
I really prefer the 1 1/2 inch D - ring binder. It large enough to hold material and small enough to comfortably fit in my hand. The 2” is more common yet is too large for me to comfortably work with. I was happy to find it because it is not readily available size in my area.