The Shires Blue Sweet Iron Tom Thumb Roller Link Jumping Bit is especially good for jumping. The Tom Thumb cheek has a lifting effect in front and offers more control and precision. The loose brass alloy discs in the center can help to soothe a fussy tongued horse. Materials: Stainless steel, blue sweet iron mouthpiece. Stainless steel is the most common material for bits. Durable, easy to clean, tasteless and it does not rust. Blue sweet iron oxidizes easily to create warmth and a sweet taste which helps with bit acceptance and encourages salivation. The addition of Brass Alloy inserts where present, help produce a warm, more palatable bit. Please note the blue color will fade with use.