Happy Mouth Roller Full Cheek Snaffle. The Happy Mouth Bits are made from hi-tech plastic moulded around a stainless steel centre for added durability, and feature an apple scent to help encourage acceptance of the bit, mouthing and help to improve performance. The Happy Mouth Bits are warmer to the touch than traditional stainless steel bits making it ideal for younger horses or horses with a sensitive mouth. The Happy Mouth Roller Full Cheek is a double jointed bit that acts on the tongue and the bars of the mouth. Read more… The double joint eliminates the nutcracker and palate action of a single jointed bit and instead applies pressure to the horse's tongue; the Lozenge has a slightly larger surface area than a french link joint and contours to the tongue. The Happy Mouth Roller Full Cheek is ideal for young and green horses as the bit applies positive pressure on the horses cheeks to aid in steering and also prevents the bit from being pulled through the horses mouth.