A lead, lead line, lead rope (US) or head collar rope (UK), is used to lead an animal such as a horse. Usually, it is attached to a halter. The lead may be integral to the halter or, more often, separate. When separate, it is attached to the halter with a heavy clip or snap so that it can be added or removed as needed. A related term, lead shank or lead chain refers to a lead line with a chain attached that is used in a variety of ways to safely control possibly difficult or dangerous horses if they will not respond to a regular lead.