Turtle Tactio Universal16MM Mouthpiece Turtle Tactio with Flex Specifically engineered to accommodate the larger or sensitive tongue. Often negates the need to shut the mouth. FlexT Universal The Universal cheek provides a number of rein options including the option of a curb strap. But whatever option you choose, the flattened underside of the cannons with their anatomy inspired recesses are held parallel to the tongue whatever riding activity you enjoy.