The Strong Flex - mouthpiece consists of three layers:
A central core providing the mouthpiece's flexibility: this flexibility stimulates the same mechanoreceptors as a straight mouthpiece.
The body providing the mouthpiece's ergonomics: pressure points are distributed to conform to the horse's mouth shape.
The outer layer providing cushioning: the Strong mouthpiece is less cushioned than a Soft or Medium mouthpiece. The information transmitted to the horse is less attenuated, allowing for better responsiveness to the rider's aids.
