The Drop Cheek has an Eggbutt like ring at the mouthpiece for the rein, with an upper cheek that has a ring at its end, to which the cheekpiece of the bridle is attached.
The mouthpiece does not slide on its ring resulting in only slight poll pressure. The cheekpieces lies flat against the horse's face, and the mouthpiece is quite fixed in the mouth and concentrates pressure on the bars.
The Bombers 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 the nutcraker action and pressure points on the tongue.