Look at how easy it is to adjust the gullet on the DP saddles. 

The gullet system can expand and contract with the easy twist of the 10mm Allen wrench (provided with the saddle). No taking the saddle apart to change the gullet between horses or seasons, just turn the 10mm hex ball wrench. Gullet max and min vary between different models and stiffness of the leather around the gullet area. The Bar Angles, Rock and Channel Width all change when you adjust a DP Saddle. Other plate systems only change the bar angle. 

Read more about the ROCK of the horse, saddle and how this changes on the DP Saddles

Read more about the CHANNEL of the saddle and how it changes on the DP Saddle