This Black Draw Rope Martingale from Al Dunning Tack by Professional's Choice is awesome.
Al Dunning says "The Draw Rope allows you to draw a horse's head into position, then transfer the pull directly to the bit or snaffle with the use of knots in the rope. This feature limits the draw after achieving the desired head position. The neck strap keeps the rope in a secure position, so when the rope is slack, your horse cannot step or trip on it. The Draw Rope is easily adjusted with the strap between the legs."