Constructed from pure UP-OCC Copper. The contacts are plated with 24K Gold, and cryogenically treated. The cable to housing clamping mechanism along with 3 pairs of different sized inserts facilitate the smallest cables all the way up to 0.935″ (23.75mm) in diameter. This 15A IEC is specified to accept up to 10awg, but we have successfully used up 8awg by splaying (forking) the wire around the clamping screw. Price to performance makes this IEC a top contender!