Shires Blue Sweet Iron Loose Ring With Roller Link
Sizes :-  4.5" , 5" or 5.5". 
Mouth thickness: 15mm, 
Ring diameter: 65mm.
The loose ring cheek has greater movement than a fixed cheek allowing it to follow the angle of the tongue which can discourage fixing and leaning. 
The loose brass alloy discs in the centre can help to soothe a fussy tongued horse.
Blue sweet iron oxidizes easily to create a warm and sweet taste, which helps with bit acceptance and encourage salavation.
Please note the blue colour will fade with use.
The addition of brass sweet iron inserts produces a warm more palatable bit.