The E9 [Latest Version is CHI Palm] is always in my bag (as well as beside my bed!)  One application is placing it on the sternum (at the girth), for either pain relief or to ground the horse, to stimulation acupuncture points to relax the whole hind quarters.  Another favorite application is stimulating the stomach alarm point to increase gut motility, hanging an E9 in a horses stall to calm and help settle them, or to help them deal with transition. So many safe and wonderful uses!