There are many bits that work in many ways.
A horse bit is the piece of equipment attached to the bridle that goes in the horse's mouth. The bit connects the rider to the horse via the reins, allowing the rider to give the horse directions. Because some bits can be harsh, it's always important to talk to horse experts, and fully understand each bit, before selecting a bit for your horse. Choose as gentle a bit as possible at first, and only work up to harsher bits if it's absolutely necessary.
Snaffle Bit
Snaffle bits are considered a gentle bit type. They are often used for beginner riders, young horses and leisure riding. Snaffle bits can be made from different types of steel, copper and rubber. Stainless steel bits are very durable and have little taste. Copper bits taste sweet to the horse, making the mouth soft on the bit. It can also make the horse drool, which is unattractive, and should not be used on pregnant mares, for health reasons. Rubber is also very soft in the horse's mouth, but only starts to taste good to the horse after time. Sweet and black iron bits are durable and tend not to chip. Snaffle bits can also have different mouthpieces. Snaffle mouthpieces are commonly divided into two or three straight or twisted pieces. There are advantages and disadvantages to each material and mouthpiece.
Curb Bit
Curb bits have long shanks, which allow attachment of the reins lower on the bit. A curb bit is typically used with a curb strap or chain, which is placed under the horse's chin. The longer shanks and curb strap or chain allow the rider to exert greater leverage on the horse and, therefore, have more control. Curb bits are sometimes made of copper and iron and can have a straight, broken or curved mouthpiece. They're common in Western riding styles.
Gag Bit
Gag bits use both leverage and pressure. They can be constructed in a number of ways, with different mouthpieces and materials. Each type of gag bit works differently and can be adjusted to exert more or less leverage or pressure. Gag bits can be very harsh on the horse, and therefore should only be used by experienced riders or those riders who are working with experienced trainers.
Pelham Bit
Pelham bits are somewhat like curb bits in that they have longer shanks and use a curb chain, allowing for greater leverage. They also have places on the lower shank for a second set of reins. Pelham bits have a slightly more complicated, curved construction, which makes the bit more comfortable for the horse. Pelhams are often steel and should be used only on horses that require higher training, but don't need as much direction as the curb bit provides.
Kimberwick Bit
Kimberwick bits work in a way similar to gag bits, providing control with a gentler, more relaxed bit. Kimberwicks, which are usually made of steel, don't have long cheek pieces, allowing for less leverage. They do have a curb chain, which allows the rider to make corrections or exert pressure.
Hackamores and Bosals
Bosals go around the horse's nose and not in the mouth like other bits. When the reins are pulled, the bosal exerts pressure on the horse's nose. Bosals can be used by themselves, with no regular bit or mouthpiece, on relaxed horses. Hackamores, like bosals, do not go in the horse's mouth.
