Champion WPCC industrial plugs have an iridium bar laser welded to the copper-cored center electrode and a platinum-iridium bar laser welded to the copper-cored ground electrode. Dual copper cores provide better voltage transfer and heat dissipation. The shape of the oversized precious metal bars improve ignition due to the increase of available sharp edges, while their iridium and platinum compositions allow for extra-long life even under the most extreme operating conditions. 13/16 male threaded upper shell for use with a transformer coil ignition system. Approved by Canadian Standards Association for Class 1 Group D Division 2 hazardous location use.