Shires Blue Sweet Iron Tom Thumb with Roller Link BitWe love this Shires Blue Sweet Iron Tom Thumb with Roller Link Bit because of the durable material and design. The Shires Blue Sweet Iron Tom Thumb Roller Link 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. Tom Thumb with Roller Link Bit Blue Sweet Iron Loose brass alloy discs in the center