Decathlon product sizing

[HayleyandBob]

Hiya all,
Just wondering if anybody has any of decathlons leather headcollars? Online it says sizes 1,2,3 and 4 so does anybody what size those equate to? I cant work out if 2 or 3 is 'cob'
thanks
Hayleyand Bob

 

[Casey76]

Three will be cob (foal/mini, pony, cob, full)