Model CPMP-4 for permanent burial - with STABLE backfill.
The CPMP-4 IR-Free DC Coupon is designed to validate corrosion prevention system operation on buried or immersed infrastructure. Its integrated permanent zinc reference electrode is positioned to measure the true carbon steel coupon potential while shielding the reference electrode from external interference, supporting accurate potential and polarization decay measurements even when connected to an active cathodic protection system. The CPMP-4 incorporates moisture-wicking materials and Corrosion Service’s patent-pending engineered STABLE backfill to improve measurement accuracy, durability, and usability without requiring complicated mixing procedures in the field.