What the Manufacturer says - The EASY-CHANGE® Gullet System offers a means of altering the width of the Elastiflex™ tree. The Elastiflex™ tree is designed to be rigid through the length of the saddle, while possessing true lateral flexion to work with the horse’s muscles. The tree width is determined by the size of gullet plate fitted between the tree points. The gullet plate governs the width of the tree from the waist to the tree points.Genuine EASY-CHANGE® Gullet Plates are engineered to be completely rigid, ensuring they cannot spread, or change shape under normal usage. Gullet plates are colour coded by size and will remain true to their size throughout their life.Only genuine EASY-CHANGE® Gullet Plates are accredited for use in saddles featuring EASY-CHANGE® Gullet System. The use of non-genuine component parts will void any manufacturer warranty.