The BC45 Petros Williams is assembled with a Williams cheek piece, which allows for multiple rein positions. If connected to the main ring the bit acts as a loose ring, but when attached to the bottom ring it promotes pole flexion by generating more positive poll pressure.

The Williams cheek piece helps to prevent drifting. 

The Petros mouthpieces rotate preventing the horse taking hold of the bit. Often good for a horse that leans or tries to take hold of the bit.

The Williams cheek piece allows for multiple rein positions. If connected to the main ring the bit acts as a loose ring, but when connected to the bottom ring it promotes pole flexion by creating more positive poll pressure.

The Bombers Control Plate is set at 45° to follow the contour of the horses tongue. Consequently, a horse who uses his tongue as a means of pushing against the bit and therefore taking control, will draw back and tuck his chin in, coming back to a better point of control.