Allows you to modify the width of the tree’s gullet to fit it to the shape of your horse. Compatible with the following saddles:
- NORTON CLUB "Rexine Evol" Dressage saddle, 
All-purpose “Rexine Evol” saddle,
 "Rexine Evol" Close Contact saddle,
- NORTON CLUB "Spring Evol" Jumping saddle,
- old NORTON "Rexine" models. 
- old ERIC THOMAS "Advance", "Jerez" and "Madrid" models.