The System III and System IV were good evolutions that needed to be taken a step further. Their contribution to later Systems was invaluable.
THE EXTRA: System III
In the quest for further progress, the Original Ortho-Flex developed this panel. It was designed to address fitting the most difficult horses to saddle; those with very pronounced shoulders, or mutton-withered and broad.
That difficult conformation is often exaggerated by a short back or croup-high conformation. It’s also seen some in warm-bloods. (For history, the "original" System III is patented as part of system or mock II (2/18/1994 -USA), and was based on three mountings, on either side of the saddle bars, allowing the panel to slide.
Ortho-Flex Saddle Company never built this system because it did not work. So there are no laws or patents to protect the current System III.
This system was then modified based on the System II with a refinement in the front part of the panel; it looks like a giant hand with five fingers. These fingers allow the panel to conform itself even more closely to the shape and motion of the shoulder, thus offering more freedom of movement.
Two results of this new construction is that it was only offered as an expensive option on some saddle models, and the use of rivets to stabilize the five fingers resulted in excessive stress which causes the fingers to either crack or break.
THE ADJUSTABLE: System IV
Pro-adjustable, tied into the extra system III patent, could be regarded as a high-tech breakthrough in flexible panel systems. The height of the panel mounting points can be adjusted quickly and easily with the use of an Allen wrench within a one-inch range.
Allowing the user to optimally balance the saddle and the rider, even on a horse with truly unusual conformational challenges.
This license from the Original Ortho-Flex Saddle Co. was sold to "Rocking R" who then changed their name to Timberline. Then was sold to K-B Saddle Shop - who kept the name.
SK Saddle, Watson Brothers Saddles (former Rocking R) for a time sold out to Ozark Mountain Saddles. Since then have terminated relations with Richard Watson and the Saddle Ranch.
This system is a hybrid of Ortho-Flex Systems I and II. These saddle companies do not feature the System II mounting method but do offer the track system at the back of the panel.
Like System I, they are also built on a single layer of Delrin, but thicker (1.25 vs the .093) allowing for rider support.
The saddletree selection is crucial to the panel and tree configuration. As is the choice of thicker Delrin enables this system to perform nicely.
The panels are also capable of some flexing in the middle, although not to the degree that the higher systems offer.
This saddle construction, like the System I, is more like a saddle with a flexible panel, than a real system.
Due to the adjustable rigging, the saddle can be positioned to compensate for this difference most of the time. This allows it to be fitted relatively well to a wide range of back types.
The Ultra Flex, Oakfield, Ultra-Flex Vario, Ultra-Flex Adjuster, Reactor Panel Saddle and lastly the Free & Easy Saddles all have a multi-layered Delrin panel.
Some have removable and or adjustable mounting spots to adjust for the limitations. Both in the panel and the tree design when fitting the saddle to the horse's shoulder and back.
Great skill and knowledge is required to achieve a good fit, because these panels are not truly self-adjusting.