Industrial Milton design coupler plug. This plug design is considered the industrial standard. Can be identified by the 3/16 In. pilot and flat bottom V-shaped ball groove. Conforms to ANSI (NFPA) T3.20.14-1990 dimensions. Conforms to ANSI (NFPA) T3.20.14-1990 dimensions. Design: Industrial/Milton Thread Size: 3/8" MNPT Material: Steel Pressure Rating: Air Rating: For Use With: 13-500 Series Part Numbers WARNING: Handling this product can expose you to Lead a chemical known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to - www.P65Warnings.ca.gov Wash hands after handling. - Nickel (Metallic)