English reins are a type of horse tack used to control and direct the horse while riding. They are typically made of leather and are attached to the bit in the horse's mouth. The rider holds onto the reins to communicate with the horse through subtle movements and signals. English reins come in various styles, such as plain leather, rubber, or braided, and can have different types of closures like buckles or clips. They are an essential piece of equipment for riding English disciplines such as dressage, show jumping, and eventing.