An attachment collar, also known as a hame or an eton, is a type of collar used to attach a horse harness to a horse's yoke. It is usually made of metal and is designed to fit around the neck of the horse. The hame is attached to the yoke by a strap or chain, while the eton is attached to the yoke by a buckle. Both types of collars are used to provide support and stability to the horse when it is pulling a load.