Made of Stainless Steel, Insulators are Molded Nylon, Includes Both Spring and Stud Mount, Also Available with SO239 Connection for Screw on Cable (SS34A) For Heavy Duty (SS34AH), Advantage is a Little Lower Profile, Spring is about 3"" Above Mount Surface, Also Available Using Ring Terminals (SS34M Medium Duty) or (SS34H Heavy Duty), Heavy Duty Models Good for Antennas to 5" Tall, 2 Year Warrant, SKU: CBDST0895