The show hack is a type of ridden show horse, exhibited to a standard first established in England. Affiliated showing and breeding of the show hacks in the United Kingdom is overseen by the British Show Horse Association. In the US and Canada, show hack is solely a form of competition open to various breeds and overseen by the USEF and Equine Canada (EC). The Canadian form of competition is more closely modeled on the British standard than that of the US. Conformation and breeding Show hacks in the UK are divided into two height classes - small hacks are 148 to 154 cm and large hacks are 154 to 160 cm. In Canada, there are also height divisions, at the discretion of show management. Ponies are defined as standing under , and horses may be divided into two or three sections; 14.2 h up to , and over 15.3 h, or 14.2 h to , over 15.2h to , and over 16 h. Australian show hacks are of any breed and are usually divided into height classes in the following categories: pony, under , Galloway, over 14 hands and under 15 hands, and Hacks over . Other classes may include pony hack ridden by a child, lady's Galloway or Hack, gent's Galloway or Hack, educated hack, sidesaddle, pleasure and heavyweight hacks. Hacks in any nation must be of elegant appearance, and show excellent self-carriage. In the UK, they are usually full or part-bred Thoroughbreds. Anglo-Arabians are particularly successful in these classes. In the United States and Canada, in addition to horses of Thoroughbred and Arabian breeding, Morgans, Ponies, Warmbloods and part-Warmblood horses also are seen, as North American competition favors a dressage-like frame and way of going. Manners and movement Hacks in the UK must have straight movement and move with "pointed" toes. Individual shows do not need to show a gallop, but should show rein back alongside the usual requirements of halt, walk, trot and canter. Workouts in Australia are similar to the UK however, a horse is often asked to show lengthening in the trot and canter and simple or flying changes of lead at the canter. In North American classes, the show hack is to show at extended, regular and collected versions of the walk, trot and canter, as well as performing a hand gallop, halt and the rein back. Particular emphasis is placed on gait