Depends on the saddle. According to my saddler the synthetic saddles were never designed to take Cair, but the leather ones were, so Cair generally sits better in a leather saddle. I have both a Leather and Synthetic with Cair and the Leather definately fits and sits better than the synthetic )which I keep for riding in crappy weather). The other weird thing is my horse takes a medium gullet in the Leather Bates Dressage saddle and has a medium tree on her Barnsby VSD, but needs a wide gullet on the wintec GP (synthetic). If I was buying again, I would go for flock.