Some equestrian manuals and competition rule books propose that ‘two fingers’ be used as a spacer to guard against over-tightening, but fail to specify where they should be applied or, indeed, the size of the fingers.
The ISES taper gauge standardises the dimensions of one and two adult fingers. When the noseband is correctly adjusted, the gauge will slide easily between the nasal bones and the noseband strap. It has been designed with additional accessories to check bit dimensions and curb shank length.
A space of two average adult fingers under the noseband allows horses to express conflict behaviour and so aligns with the principles of ethical equitation. That said, it does not permit horses to perform the full repertoire of behaviours, including yawning.
ISES recommends That all equestrian sports should require that the tightness of any noseband is checked by a steward at the nasal midline. For fairness and objectivity, a taper gauge inserted under the noseband should be used for this purpose. The taper gauge should be placed without force and be clearly marked to show the desired stop which, in alignment with established industry guidance, is the dimensions of two average adult fingers. Riders should be advised and encouraged to use the same gauge in practice.