Fully adjustable neck strap, alongside an adjustable girth loop - for a great fitA running martingale is best used on horses that tend to raise their head too high to avoid contact or throw their head up to avoid workThe running martingale works by adding pressure on the reins through to the bit on the horses mouth whenever their head is above the desired point. This pressure/leverage encourages the horse to lower its head.Head raising can be a behavioural issue or a sign of pain. It's recommended you seek professional help if your horse is regularly throwing his head up when riding.