PENETROX A Consists Of A Natural (Petro - Leum) Base Vehicle In Which Zinc Particles Are Suspended, For Aluminum To Aluminum, Aluminum To Copper Applications And Aluminum Conduit Threads. It Is Not Recommended For Use With Rubber And Polyethylene Insulated Conductors, UL Listed To 600 Volts. Dropping Point (minimum): 230 DEG F. Voltage Rating: 600 V