 Larger ports press on the hard palate (roof of the mouth) when the reins are pulled, act as a fulcrum, and transfer that pressure onto the bars.Recent research has shown that the port must be 2-2.5" (5–6 cm) or more in height before it touches the hard palate.Thus the mildest port height is not necessarily the lowest ported bit, as commonly believed; it can also be the highest port possible that does not contact the hard palate.