Regal Chemicals 29-60350-40 Multi Shock Blended Di-Chlor Shock. MULTI SHOCK actively destroys the chloramines and organic residue in your spa water. It is an oxidizing and a clarifying treatment only. MULTI SHOCK must be used with a disinfectant and will efficiently accelerate the elimination of organic contaminants in your spa water. This re-activating treatment restores water's sparkle to your spa water while extending the effect of chlorine. Suitable for all spa surfaces.