SIZING YOUR DUALLY:
Red size fits medium-large ponies and weanlings of most horse breeds, as well as yearlings of large breeds and arabian adults 300-700 pounds
Nose – Minimum 19.5 in (49,5 cm), Maximum 28 in (78,7 cm)
Head – Minimum 29 in (73,7 cm), Maximum 39.5 in (100,3 cm)
Cheek – From Ring Ring 7 in (17,8 cm)
The size of the head matters more in fitting a Dually than the weight of the horse.