If you would describe your horse as something with the following;
Heavy in your hands.
Tries to avoid the bit, fussy in the contact
Strong, usually lean/pull on the bit
Won't accept the bit or just for short times. Usually drops/chew on the bit and feel uncomfortable.
The effect of a Kimblehook is more direct than curbs with longer shanks. The lower the rein is placed on the sides, the sharper this bit will be.
The mouthpiece of Carl follows the natural shape of the mouth with a short centerpiece that lay flat against the tongue and eliminates palate interference. It breaks to the outside of the tongue, it also softens excessive pressure to the center of the tongue and presents a more consistent feel across the mouth.
A horse with a sensitive tongue will begin to accept the contact and be more willing to work.
This mouthpiece even suits horses with a low palate together with a big tongue. These horses are difficult to find a suitable bit for.