Zinc-plated shell with grounding indents on the plugs. Insert is black thermoplastic, rated 94V-O. Contact Rating (with 20 AWG Wire): 7.5 Amps. Termination Resistance: 5K megohms. Engagement Force: 12 Oz. Separation Force: 0.75 Oz. Mating Force: 8 Oz. per contact. CONTACTS NOT INCLUDED. Uses contact size 20 DF contacts.