A bit guard is a specialty piece of horse

Horse

The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

 tack

Tack

Tack may refer to:* A type of cut nail, used in upholstery, shoe making and saddle manufacture* Horse tack, harness and equipment to allow horse-back riding* Tack , quick, temporary stitching intended to be removed...

: a washer

Washer (hardware)

A washer is a thin plate with a hole that is normally used to distribute the load of a threaded fastener, such as a screw or nut. Other uses are as a spacer, spring , wear pad, preload indicating device, locking device, and to reduce vibration...

, usually made of flexible rubber, that is sometimes used in pairs on a bit

Bit (horse)

A bit is a type of horse tack used in equestrian activities, usually made of metal or a synthetic material, and is placed in the mouth of a horse or other equid and assists a rider in communicating with the animal. It rests on the bars of the mouth in an interdental region where there are no teeth...

.

Reasons for using a bit guard include:

• to protect the horse's lips from chaffing or pinching by the bit rings
  Bit (horse)
  A bit is a type of horse tack used in equestrian activities, usually made of metal or a synthetic material, and is placed in the mouth of a horse or other equid and assists a rider in communicating with the animal. It rests on the bars of the mouth in an interdental region where there are no teeth...
  
  
• to provide a better fit when the bit is too wide for the horse's mouth
• to prevent the bit rings from being pulled through the horse's mouth

A pair of bit guards is placed on a bit by stretching them to pass over one bit ring. Then the bit is attached to a bridle

Bridle

A bridle is a piece of equipment used to direct a horse. As defined in the Oxford English Dictionary, the "bridle" includes both the headstall that holds a bit that goes in the mouth of a horse, and the reins that are attached to the bit....

. The bridle is then put on a horse

Horse

The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

 so that the bit guards lie outside of the horse's mouth. Bit guards are used with loose ring snaffle bits, gag bit

Gag bit

The gag bit is a type of bit for a horse. With two sets of reins, the gag bit gives a rider the ability to use either a standard direct action or a gag action. In this, the gag bit is related to a Pelham bit and a double bridle...

s, and pelham bit

Pelham bit

A pelham bit is a type of bit used when riding a horse. It has elements of both a curb bit and a snaffle bit. In this respect a pelham bit functions similar to a double bridle, and like a double bridle it normally has "double" reins: a set of curb reins and a set of snaffle reins. Because it has...

s. Bit guards are used more often in jumping events, such as eventing

Eventing

Eventing is an equestrian event comprising dressage, cross-country, and show jumping. This event has its roots in a comprehensive cavalry test requiring mastery of several types of riding...

 and show jumping

Show jumping

Show jumping, also known as "stadium jumping," "open jumping," or "jumpers," is a member of a family of English riding equestrian events that also includes dressage, eventing, hunters, and equitation. Jumping classes commonly are seen at horse shows throughout the world, including the Olympics...

, and in polo

Polo

Polo is a team sport played on horseback in which the objective is to score goals against an opposing team. Sometimes called, "The Sport of Kings", it was highly popularized by the British. Players score by driving a small white plastic or wooden ball into the opposing team's goal using a...

. They are not permitted in competitive dressage

Dressage

Dressage is a competitive equestrian sport, defined by the International Equestrian Federation as "the highest expression of horse training." Competitions are held at all levels from amateur to the World Equestrian Games...

, and are not used in horse show hunt seat

Hunt seat

Hunt seat is terminology used in the United States and Canada to refer to a style of forward seat riding commonly found at American horse shows. Along with Dressage, it is one of the two classic forms of English riding. The Hunt seat is based on the tradition of fox hunting...

 competition.

A pair of bit guards with an integral forked strap, to suspend them from the browband or crownpiece of the bridle, are known as cheekers (see Frentera

Frentera

A frentera is a part of some halters and bridles, usually on a horse. It is a cord, strap, or chain on the face of the horse that is attached to the crownpiece or browband and runs down the horse's face to the noseband or bit rings. A frentera can be split at the top to pass on either side of the...

).

Bit burr

Resembling a bit guard is a bit burr (sometimes burr bit, also bubble cheeker in Australia), which has teeth laid against the horse's cheek. The burr bit was for a time widely used on coach horses in New York City, until the use was stopped in part through the efforts of Henry Bergh

Henry Bergh

Henry Bergh founded the American Society for the Prevention of Cruelty to Animals in April, 1866, three days after the first effective legislation against animal cruelty in the United States was passed into law by the New York State Legislature...

 circa 1879. Bubble cheekers are approved for use in thoroughbred racing in Australia.