The Loose Ring Tube cheek pieces lies flat against the horse's face giving a more solid feel against the side of the face, while preventing pinching of the lips and the bit being pulled through the mouth. The mouthpiece is quite fixed in the mouth and concentrates pressure on the bars but the loose rings allow for a quick release.
Our Snaffle is a popular bit due to the curved mouthpiece which distributes pressure more evenly over tongue and bars. With the offset centre link it will reduce nutcraker action and pressure points on the tongue.
The Square Twist will create more pressure points on the mouthpiece which will make it stronger than the Round Twist and Smooth.