CS and CN sprays basically contain irritants which effect the tear ducts and cause a watering/tearing of the eyes. OC/Pepper sprays are inflammatory in nature causing more varied reactions, including breathing restrictions.
OC (Oleoresin Capsicum) is the organic oil taken from a pepper plant. The percentage amount shown on a cannister shows how much of the “ingredient” is in the cannister. It doesn’t show how potent or hot the spray is. The SHU (Scoville Heat Unit) value shows how “hot” the spray is.