A lead, lead line, lead rope (USA) 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.
A lead can be made from a variety of materials, including cotton, horsehair (woven or braided hair, usually from a horse's tail), leather, nylon or other synthetic materials. Lead ropes, as the name implies, are round and made of various types of rope, usually between 5/8 and 3/4 inch (about 2 cm) in diameter. Lead lines are usually flat webbing or leather, and are generally .75 to 1 inch (1.9 to 2.5 cm) wide, though may be narrower for show use. Flat lines are less bulky and more comfortable in the hand for leading and animal, but may lack adequate strength for tying.
A lead most often attaches to the halter with a sturdy snap. In some cases, the lead is tied or spliced permanently to the halter. A lead for a horse usually is in the range of 9 to 12 feet (2.7 to 3.7 m) long, but longer and shorter lengths are seen.
The lead shank consists of a lead, usually a flat line, with a chain end, or, less often, thin nylon or rope. The chain end ranges from 18 to 30 inches (46 to 76 cm) long and has a snap or clip on the end that attaches to the halter, and a ring on the other end that is attached to the lead line. Some lead lines are permanently sewn to the chain shank, others have buckles or clips allowing the chain to be removed. Lead shanks are usually used on potentially difficult or dangerous horses, such as stallions or those that, for various reasons, will not respond to a regular lead. For this reason, in some regions, lead shanks are sometimes called "stud chains." They are also commonly seen on in-hand horses of all ages and sexes at some horse shows, as the chain shank can also be used to transmit commands quickly but inobtrusively, encouraging a prompt response from the horse.
For aesthetic purposes, the lead may be the same color as the halter, and sometimes even made of the same materials.