The Founder Pad is made up of a 3/8″ yellow pad with a half blue pad of either 1/2″ or 3/4″ thickness. The thickness depends on the rotation, weight of the horse and necessary amount of stabilization required. 1/2″ is used up to 9 degrees of rotation and 3/4″ are used for anything over 9 degrees. Founder pads are used by The System team, in most cases, as the first set of pads when a new founder case in taken on. In chronic cases of founder the pad gives comfort as heels are reduced in height to de-rotate the coffin bone. It allows for enough resistance to allow the horse to find comfort in the heels and compress as the horse weights the heels. Their purpose is primarily to help stabilize the coffin bone in hoof, but they are also intended to provide support to the bony column and to the remaining connective tissues, stimulation to the frog, sole and bars of the foot to help reestablish blood supply to the areas most affected in the foot, to provide cushion for the horse so that he will be able to move and perform light exercise hand walking for stimulation and circulation and they allow the horse to, as Tommy Lee says, find his spot, meaning it allows the horse to find a certain amount of comfort, which the horse is likely better at placing exactly were its needed instead of the human trying to second guess where the support is needed.
See pictures of the founder pads to see how a founder pad wears.  
 
***Slipper size vs pad size: Small slipper takes Small pad, Small/Medium takes Medium pad, Medium slipper takes Large pad, Large slipper takes X-Large pad.    *** Slippers Sold individually.
 
PAD SIZE
Small 4.75" x 5", Medium 5.25" x 5.5", Large 5.5" x 6"
 
THICKNESS:
1/2", 3/4"