The tom thumb bit has a lifting action so can help reduce the horse leaning on the bit. Attaching the reins to the lower rings will increase the severity, so should be used with care. Mouthpiece thickness 14mm. Cheek height: 135mm. Blue sweet iron mouthpieces oxidise easily to create warmth with a sweet taste which helps with bit acceptance and encourages salivation. Please note the blue colour will fade with use. Stainless steel is used for the cheeks due to it being durable, easy to clean and resistance to rust.