The Eggbutt shape will prevent pinching of the lips. The release is slower and some slight poll pressure is introduced. The Eggbutt Gag is the gag version of the Eggbutt is stronger and will create more leverage on the mouthpiece whilst at the same time introducing more poll pressure.
The Buster Roller link in the middle is shortened to 40mm which increases bar and tongue pressure making the bit sharper than conventional link bits. The increased pressure on the bar will lift the head and the roller will increase pressure on the tongue bringing the chin in. Best suited for a horse with a low head carriage and which leans on the bit.
Disclaimer: Sweet Iron will oxidize when it comes into contact with mositure, this oxidation process encourages salivation which improves acceptance of the bit. This process changes the blue colour of the Bomber bit to a brownish grey. If not used for a while, any build-up may be removed with a scourer and wiped with a damp cloth.