The Mattes Sheepskin Correction Pad system is ideal for horses that are either out of shape/from or returning from an injury, where incremental correction may be needed as the horse’s back and shoulders gain muscle tone. It is also good for one-sided horses or as a rear or front riser. The unique design of the Mattes Sheepskin Correction Pad incorporates four pockets along the spine - two front pockets and two rear pockets. Shims (12 included) fit into these pockets for a completely custom fit. You can shim the pad in one pocket, or in all four pockets, depending on the need of each particular horse. As the horse gains muscle you can eliminate the shims one by one to give him room to muscle up into the saddle. This half pad has a heavy-duty outer cotton quilt, with the patented Mattes stitching pattern.