[b]Mats Sweet iron Mouthpiece goes with the Otto combination bit. When you order a mouthpiece for your combination bit, please select a size that's 1cm larger. [u]Please understand:[/u] We make the mouthpieces just for you once you order. So, you can't return or exchange them. We create them from our standard loose ring bits to fit your needs.[/b] This lets us give you a variety of mouthpiece options and sizes for your custom bit! Fager Mats is a good choice if you would describe your horse as the following; * Can be inconsistent in the connection. * Fussy in the contact. * Stiff, yet sensitive. * Refuses to accept the bit or will only accept it for short periods. * Drops/chews on the bit, generally feeling uncomfortable.