The Lameness Kit is a good kit for a foundered or foundering horse.  
 
Here is what each pad is great for:
2 pair each 3/4″ and 1/2″ Founder pads
3 pair  3/8" RWB (Laminitis/Abscessing/Founder)
3 pair 1/2" Natural (Heel and/or back of hoof pain)
3 pair 1/2 " Blue (Thin soles or sore soles)
 
***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"