"Aroclor" was the original trade name given to PCB (Polychlorinated Bipheyl) mixtures by the producer, Monsanto Company.
Aroclor PCB mixtures are typically identified with a 4 digit number, where the first two digits refer to the product series; the second two indicating the percentage of chlorine by mass in the mixture. For example Aroclor 1260. (Series 1200, 60% chlorine by volume).
Different Aroclors were used at different times and utilized for various applications globally.