I love this very simple but very effective gadget.
First, what's a gadget? Anything used to artificially affect the horse's way of going, for better or for worse. You don't have to be afraid of the word, or using gadgets, but you do have to use them properly.
Why do I like it? Simplicity. Mine is a rope, a knot to shorten it, and two snaps. That's it. I also like it because it allows the horse to figure things out for himself and it doesn't punish the horse for going with his head in the air, but encourages them to lower their heads and work over their back. I like using it on high headed or tense horses.
We all know that horses are supposed to work over their back, but it seems like most horses don't know this! I like this because it helps show the horse "the way" The horse follows the contact down and out, his back goes up, and he goes, "hey! this feels great!"
I'm using it right now for Stella once a week where we lunge instead of ride. I want her to learn how to put her head down, stretch her neck, and use her back without being worried about what her rider is doing, and without something forcing her into position which defeats the purpose of relaxation.