Drop Noseband

Could someone please explain the drop noseband and how it works?

http://www.sustainabledressage.com/tack/bridle.php

There's a good link... nosebands are discussed just a bit down the page :)

The drop noseband sits below the bit in the chin groove, rather than above and near the cheekbone, like a cavesson. The general idea is to stabilize the bit and prevent the horse crossing his jaw or gapping his mouth. The flash noseband was actually designed as an improvement on the drop for jumpers, since attaching a standing martingale to the drop can be dangerous. The flash has the action of the drop with a safe attachment for a martingale. I think I read somewhere that the drop noseband was originally invented at the Spanish Riding School...