What's the use of a martingale?
A martingale prevents the horse from tilting its head too high, which would normal result in loss of contact. A martingale does not disturb normal rein contact as long as the horse keeps its head in the correct position. A martingale is attached to the girth with a loop and the other two ends have rings to lead the reins through. To prevent the martingale from slipping up or down so-called martingale stoppers can used.
What is the point of a Market Harborough?
A Market Harborough is sometimes called a German Martingale. A Market Harborough prevents your horse from tilting its head too far up and from stretching its neck too far forward. The Market Harborough does not interfere with a correct head position, when attached correctly it helps keep the horse's head in the correct position.
The Market Harborough is attached to the girth by means of a loop. Special reins are attached to the bridle's bit; these reins have D-rings to which the Market Harborough is attached. A Market Harborough, or German Martingale, is easily adjusted because of the many D-rings on the reins.