CMP Zinc Pencil Anode with NPT Plug for Marine Engine Cooling Systems Anodes/Zincs

The CMP zinc pencil anode with NPT plug is a sacrificial engine anode (also called an engine zinc or pencil zinc) made for the raw-water cooling systems of marine engines. It threads into the engine's heat exchanger, manifold, or cooling circuit. There it corrodes in place of the engine's metal parts and helps protect them from galvanic corrosion.

Key Features:

• Sacrificial zinc element: The zinc rod is consumed first, so it takes the galvanic attack instead of the surrounding metal components.
• Threaded NPT plug: The plug threads directly into a matching NPT port on the cooling system.
• Pencil-style design: The compact rod fits inside heat exchangers, coolers, and engine water passages.
• Made for marine cooling systems: Zinc anodes like this are commonly used in inboard engines, generators, and other raw-water-cooled marine equipment.

Maintenance Note: Pencil zincs wear away as they work. Inspect them regularly and replace them once a large share of the zinc has eroded. Many sources suggest replacing them each season or when about two-thirds is gone, whichever happens first.

Choose the child option that matches your engine's port thread size and required zinc length. Use it to keep your engine's cooling system protected from corrosion.