NAF Off DEET Power Spray 750ml. NAF Off DEET Power Spray offers long lasting protection against flies, horseflies and insects. NAF Off DEET Power Spray comes in a handy trigger spray and contains the powerful insect repellent DEET. Contains: DEET (N,N-Diethyl-m-toluamide) 19.8% w/w, IR3535 (Ethyl Butylacetylaminopropionate) 5% w/w 750ml.