This Square Port bit has a slight angle on the port to lay nicely in a horse's mouth, that way the port is not adding palate pressure. Ridges in the twisted wire bars motivate horses to not brace against the rider's hands.  This bit would be great for a seasoned rope horse that you need to "hold" in the box by the angle on the port and smooth bar mouthpiece will rest nicely in a horse's mouth. The square edges on this port is more pressure than that of a rounded port, thus encouraging a horse to flex vertically at the poll.

• Dutton Bits Calvary shank Square port with copper rollers 5'' Mouthpiece 
• Purchase: 2.5" 
• Shank: 5" 
• Cheek: 8" 
• Made in the USA