The term 'Horse Rider's Strap' is a reference to a REIN, which is a piece of equipment used by horse riders to control their horses. A REIN is a long, thin strap made of leather, nylon, or other materials that is attached to the bridle of a horse and held by the rider in order to control the horse's movements. The REIN is an essential part of horse riding, as it allows the rider to communicate with the horse and guide it in the desired direction.