The Big Ring Gag is stronger than the usual Loose Ring and Eggbutt as the ropes going through the rings create leverage which will exert more pressure through the mouthpiece whilst at the same time introducing more poll pressure.
The Barrie is a severe bit due to the centre links of the two pieces being offset by 20mm giving it a double nutcracker action, which creates more tongue and bar pressure.
The Square Twist will create more pressure points on the mouthpiece which will make it stronger than the Round Twist and Smooth.
Good for strong older horses.
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.