The Brass Impact Head works with or replaces 1/2 In. impact or impulse heads. It covers areas of 25 Ft. to 40 Ft. radius and can be adjusted from a partial to full circle.Covers areas from 20 Ft. to 40 Ft. radius in a part or full circle Anti-backsplash arm Works with most 1/2 In. impact or impulse heads 1/2 In. male threaded For outdoor use with cold water only