We love this Easy-Change Gullet System because these can be purchased individually as needed.  

An individual EASY-CHANGE Gullet for use in saddles featuring the EASY-CHANGE Gullet System.  The EASY-Change Gullets are available in the following individual sizes:

• Narrow/Yellow
• Medium/Black
• Wide/Red
• Medium Narrow/Green
• Medium Wide/Blue
• Extra Wide/White
• 1XW/Light Lilac (WIDE Gullet System)
• 2XW/Medium Lilac (WIDE Gullet System)
• 3XW/Purple (WIDE Gullet System)
• 4XW/Dark Purple (WIDE Gullet System)

Also available  which includes the gullet gauge tool.

The EASY-CHANGE Gullet System is exclusive to Bates Saddles and Wintec Saddles and offers a means of altering the width of the Elastiflex tree in your saddle. The Elastiflex tree is supported by the rigid gullet at the head and possesses true lateral flexion to work with your horse’s muscles. The tree-width is determined by the size of the 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 color-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 the EASY-CHANGE Gullet System. The use of non-genuine component parts will void any manufacturer warranty. 

Together EASY-CHANGE Gullet System and the  offer a complete fitting solution with an unparalleled scope of adjustment for your horse’s absolute comfort and peace of mind. Featuring front, center, and rear risers in varying depths, The EASY-CHANGE® Riser System enables you to make adjustments within the saddle panel for optimal balance and clearance. All adjustments are measurable, symmetrical, and completely reversible, ensuring total confidence.