Nathe Gag bit 20 mm with flexible Mullen Mouth

Item number: 40434


Thickness 20 mm
Ring-Ø70 mm
  • a good choice for horses that are top heavy, for example on the course.
  • for the sensitive rider’s hand
  • impact on mouth, poll and corners of the mouth
  • pull-up effect due to pressure development on the jaw angles
  • can be used with one or two pairs of reins
  • gentle on the corners of the mouth thanks to the bit guards
  • steel core provides safety
  • no warranty for bits or teeth marks
This Nathe Gag bit with flexible Mullen mouthpiece provides an even action on the tongue, neck and corners of the mouth. It is a good choice for horses that are reluctant to be bridled and tend to be strong in the mouth. As the bridle exerts pressure on the corners of the mouth, there is an additional pulling effect. This makes it possible to achieve fine communication even with horses that tend to be heavy on the forehand, for example, when tackling challenging technical questions while on course.

The precise effect of this bit makes it particularly suitable for riders with sensitive hands. The rider can choose to ride with one or two pairs of reins.

Nathe bits are suitable for sensitive and mouth sensitive horses. Made from high quality thermoplastic, they are anti-allergic, temperature resistant and dimensionally stable. The side-mounted bits also help to protect the corners of the mouth.
More Information
Ring typeGag bit
Thickness 20 mm
MouthpieceMullen mouth
Ring-Ø70 mm

Prerequisite for a correctly fitted bit is a correctly and not too tight buckled noseband. The bit should be chosen in the appropriate size and must be fitted close to the corners of the mouth. If you cannot put the headpiece of the bridle over the horse’s ears easily, the bit is buckled too high. If the cheek piece is shaking after taking up the reins, the bit is buckled too low.

All Sprenger bits that are marked with an arrow at the side of the mouthpiece have to be positioned correctly in the horse’s mouth. In order to ensure Optimum effectiveness the arrow has to point forwards on the left hand side.

Conventional loose ring

Bits not being marked with an arrow may be positioned in any direction. This normally applies to standard single jointed or straight mullen mouth bits. Standard single jointed bits have a production related characteristic: one part of the mouthpiece is longer than the other which results in stronger influence on one tongue half. To prevent exerting uneven pressure in the long term you should turn the bit around periodically.


Turnado bit

If you want to avoid the problem of exerting uneven pressure due to a single jointed bit you can use our Turnado or single jointed Dynamic RS bits. The joint of these bits has been turned forward by 45 degrees in order to guarantee an even distribution of pressure on both sides of the tongue.

The bit operates like a communication channel between rider and horse. As the mouth is one of the most sensitive parts of the horse’s body it is important to treat it very carefully. Therefore a bit should be sized and fitted to the individual anatomic shape of the mouth as well as to the characteristic needs of the horse and should never be uncomfortable or awkward in any way.

There are two factors to consider when choosing the size of a bit:
- Width
- Thickness


Bits with loose rings

With correct attaching of bit with loose rings, there should not be more than 0.5 cm space on the right and left between mouth corner and bit ring. The ring should always be freely movable and should not pinch the mouth corner.


Bits with fixed cheeks

e. g. eggbutt, Full cheek or D-Ring bits

Bits with fixed cheekpieces such as eggbut or D-ring bits should fit closely to both mouth corners and must therefore be Chosen smaller than loose ring snaffles. Due to the contact of the cheek to the corner of the mouth the rider achieves additional support from the rein aids.



Double bridle

The double bridle consists of a weymouth and a bradoon. The bradoon should equal the standard snaffle in size and shape because it lies at the same position in the horse’s mouth. The weymouth is positioned a Little bit lower where the horses head gets thinner. We recommend to choose the weymouth 0,5 to 1 cm smaller than the bradoon in order to achieve the best possible effect and to make it most comfortable for the horse.




The thickness of a bit should be adapted to the anatomic needs of your horse. A study of Sprenger and the Veterinary University of Hanover found that the oral cavity of horses is fairly small and the available space for a bit can be very limited. You cannot draw conclusions from the body size of your horse to its oral cavity.



To find out what thickness you should choose for your horse you can try the “2-finger-test”. You just need to put your index and middle finger together and insert them in the horse’s mouth at the point where the bit usually lies. A small gap between the upper and lower jawbone will exert pressure on both fingers and will require a thinner mouthpiece (14 – 16 mm) in order to fit comfortably. If you feel only little or no pressure on your fingers there is space for a thicker mouthpiece (16 - 18 mm).


Using a too thick bit will exert pressure on the sensitive palate and will cause bruises and injuries. The horse might react with head tossing, gaping its mouth or jerking on the reins.