What is a “Bit”?

A bit consists of a mouthpiece and a cheekpiece. The mouthpiece will rest inside of the horses mouth in the interdental space. The cheekpiece will be outside the horses mouth, against the face. 

Interdental Space

The interdental space refers to the space that is not occupied with teeth, this is between the cheek teeth (towards the back of the mouth) and the incisors or canine teeth (towards the front of the mouth). 

This unoccupied space allows the mouthpiece of the bit to rest in the mouth without having the jaw open or interfering with the horse’s teeth.

Getting the fit of the bit correct is vitally important to the horse’s comfort. A bit that is far too small can cause pinching of the lips, but a bit that is too large can cause even more problems.

We have only been taught to look at how the bit fits the outside of the lips, without any consideration of how the bit functions inside of the mouth. When the mouthpiece is too large, the joints move, and the curves can sit incorrectly in the mouth. This leads to the mouthpiece applying pressure to areas it should not be.

An oversized bit will also create too much movement in the mouth. Allowing the bit to slide from side to side through the mouth. This movement causes discomfort as well as a background noise to the rider’s aids. When it comes to selecting the correct size, we need to take into account the horse’s actual mouth measurement but also consider how fleshy the lips are, how wide the lower jaw is and where the horses teeth are in relation to where the bit will sit.

To further learn about sizing:


A mouth piece is the part of the bit that goes inside the horses mouth.

The mouthpiece is where majority of the pressure application comes from, the pressure is determined by the shape, width and functionality of the mouthpieces’ design.

At Bombers we have 6 categories of Mouthpieces: 

  • Solid
  • Semi-broken
  • 1-Break
  • 2-Break
  • Flexible
  • Cable
Solid Mouthpieces
A solid mouth piece has no joints or movement. Solid mouth pieces can be further divided into ported and non-ported mouth pieces.
Semi-Broken Mouthpieces
Semi-broken mouth pieces have very limited movement as the joint hinders movement. A semi-broken mouth piece will have more movement than a solid mouthpiece and less movement than a broken or flexible mouth pieces. Semi-broken mouthpieces can be further divided into ported and non-ported mouthpieces.
1-Break Mouthpieces
1-Break mouth pieces can be referred to as a single jointed mouth piece. A 1-Break joint has more movement than a semi-broken mouth piece.
2-Break Mouthpieces
2-Break mouth pieces can be referred to as double jointed mouth pieces. A 2-Break mouth piece has more movement than a semi-broken mouth piece. 2-Break mouth pieces can be further divided into ported and non-ported mouth pieces.
Flexible Mouthpieces
Flexible mouth pieces are mouth pieces (as the name indicates) are FLEXIBLE. Many jointed mouth pieces (such as waterfords) fall under this category, as well as non-metal mouth pieces that are bendy ( such as a flexible mullen, leather mullen and moulded mullen)
Cable Mouthpieces
Cable mouth pieces remove the metal joints and replace them with cable. The cable therefore removes any pressure points that linked metals would create. Cable mouth pieces also have a spring-back action, this hinders mouth pieces like a cable snaffle to create a squeeze on the bars, whereas a metal snaffle would create excessive squeeze on the bars.

What are the branches of a mouthpiece?

The branches of the mouth piece is the piece of the mouth piece that rests on the bars.


A cheek piece is the part outside of mouth to which the bridle and reins are attached to.

A Cheekpiece can assist to increase or decrease pressure applied. Cheekpieces are also sometimes determined by discipline.

At Bombers we have 3 categories of Cheekpieces:

  • Loose
  • Fixed
  • Fixed & Loose
Loose Cheekpieces

A loose cheek piece slides through a hole in the mouthpiece. A loose ring allows pressure to be applied slowly as the ring to which the bridle and reins attach slide through the hole in the mouth piece when contact is taken up. Pressure is also released quickly as once the reins relax, the bit will return to a neutral position in the mouth.

Fixed Cheekpieces
A fixed cheek piece is directly attached to the mouthpiece. A fixed cheek piece applies slight pressure to the side of the face. Fixed cheekpieces prevent the bit from sliding through the mouth, they allow us to fit the snuggly as there is no danger of pinching. Fixed cheekpieces have a slower release of pressure than a loose type, as well as a quicker application of pressure.
Fixed & Loose Cheekpieces
A fixed & loose cheek piece offers the best of both worlds. The cheek piece is fixed to the mouth, but there is a loose ring that is within or attached to the cheek piece. This combination has all the benefits of a loose ring but without any need to worry about pinching. The also add cheek pressure.