Brass. Thread size: 1/4" Female NPT x 3/8" Male NPT. 1 per card. Thread Size: 1/4" FPT x 3/8" NPT \nMaterial: Brass \n WARNING: Handling the brass parts of the 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 handlin - Lead