NOCO battery terminal protectors — oil-based anti-corrosion washers, Pack of 50, top/side-post fit

NOCO NCP2 B603 oil-based battery terminal protectors are felt washers pre-saturated with a long-lasting corrosion inhibitor to prevent acid-fume damage on top- and side-post batteries.

Left unchecked, battery terminals and surrounding metal can corrode from acidic fumes and moisture, reducing electrical contact and shortening battery life. These NOCO anti-corrosion washers are made from organic non-woven felt infused with an oil-based compound that resists drying or evaporating, creating a durable barrier against corrosive deposits. The pack includes 50 washers designed to fit most common automotive, marine, and powersport battery posts.

How do these washers stop battery corrosion?

The felt washers are saturated with an oil-based preservative that blocks acid vapors and moisture from reaching metal surfaces. By forming a physical and chemical barrier, they help maintain clean terminal contact and reduce the likelihood of rust and crystalline buildup.

• Saturated non-woven organic felt traps and neutralizes acid fumes.
• Oil compound remains pliable and does not dry out over time.
• Creates an impenetrable layer over terminal surfaces.
• Reduces white or green corrosion deposits that impair conductivity.

Will these fit my battery’s top-post and side-post terminals?

Yes — each washer has a removable inner ring so a single design accommodates both top-post and side-post configurations. The ring can be popped out to enlarge the center hole for side-post studs, making the product versatile across different battery layouts.

• Removable inner ring adapts to multiple post diameters.
• One washer design works for both top and side post batteries.
• Slim profile fits under clamps without causing interference.
• Pack quantity suits multiple batteries or seasonal replacements.

How long does the protective treatment last and is maintenance required?

The oil-based inhibitor is engineered to remain effective for the life of the washer because it resists drying and evaporation. While the treatment itself is long-lasting, periodic inspections of terminal condition are recommended; replace washers if they become saturated with heavy corrosion or physically degraded.

• Oil-based formula resists evaporation for extended protection.
• No routine reapplication of product required under normal use.
• Inspect during regular vehicle maintenance or battery checks.
• Replace washers when heavily contaminated or damaged.

What improvements to electrical performance can I expect?

By preventing buildup that interrupts metal-to-metal contact, these washers help preserve reliable current flow and reduce voltage losses at the terminals. Maintaining clean, corrosion-free connections supports consistent cranking power and can reduce unnecessary electrical resistance in accessory circuits.

• Helps maintain solid clamp-to-post contact for stable conductivity.
• Reduces intermittent starting issues caused by corroded terminals.
• Supports optimal charging and accessory performance.
• Useful for vehicles, marine batteries, and stored equipment.

Who is this product for? These NOCO NCP2 B603 washers are aimed at vehicle owners, fleet managers, marine operators, and anyone who wants a simple, reliable way to prevent terminal corrosion without frequent reapplication. They’re especially helpful for older batteries, equipment stored outdoors or in damp conditions, and users looking to reduce maintenance time while preserving electrical performance. Packaged in a 50-count set, they suit multi-battery use, workshops, and seasonal upkeep.