---
product_id: 23782678
title: "Anodes, CMR03M, Magnesium Rudder & Trim Tab Disc Anode (0.5 H x 3.75 OD x 0.34 ID) – Marine Boat Sacrificial Anode for Freshwater Corrosion Protection"
brand: "martyr"
price: "VT10831"
currency: VUV
in_stock: true
reviews_count: 8
category: "Martyr"
url: https://www.desertcart.vu/products/23782678-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode-0
store_origin: VU
region: Vanuatu
---

# Optimized for freshwater use ISO 9001 certified precision Superior corrosion defense Anodes, CMR03M, Magnesium Rudder & Trim Tab Disc Anode (0.5 H x 3.75 OD x 0.34 ID) – Marine Boat Sacrificial Anode for Freshwater Corrosion Protection

**Brand:** martyr
**Price:** VT10831
**Availability:** ✅ In Stock

## Summary

> 🛥️ Stay ahead of corrosion—because your boat deserves the best defense!

## Quick Answers

- **What is this?** Anodes, CMR03M, Magnesium Rudder & Trim Tab Disc Anode (0.5 H x 3.75 OD x 0.34 ID) – Marine Boat Sacrificial Anode for Freshwater Corrosion Protection by martyr
- **How much does it cost?** VT10831 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.vu](https://www.desertcart.vu/products/23782678-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode-0)

## Best For

- martyr enthusiasts

## Why This Product

- Trusted martyr brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Impurity-Free Composition:** Crafted without iron or contaminants to maximize anode lifespan and effectiveness.
- • **Versatile Marine Protection:** Ideal sacrificial anode for rudders and trim tabs, safeguarding vital boat components from corrosion.
- • **Trusted by Professionals Worldwide:** Backed by a 4.8-star rating and global reputation for reliability and quality.
- • **Tailored Alloy for Freshwater Mastery:** Magnesium alloy specifically formulated to deliver unmatched protection in freshwater environments.
- • **Precision Engineered for Peak Performance:** Pressure diecast with ISO 9001 quality control ensures flawless fit and durability.

## Overview

The Martyr CMR03M Magnesium Rudder & Trim Tab Disc Anode is a precision diecast sacrificial anode designed exclusively for freshwater corrosion protection. Manufactured under strict ISO 9001 standards, it features a high-purity magnesium alloy that outperforms alternatives by preventing rust and degradation on marine rudders and trim tabs. Lightweight and perfectly sized, this anode offers cost-effective, long-lasting defense trusted by boaters worldwide.

## Description

Alloy selection is critical for proper protection. Zinc is recommended for use in salt water (not recommended for fresh water). Aluminum is designed for use in salt or brackish water, and has better performance and longer-lasting protection than zinc. Magnesium is intended ONLY for use in fresh water, and is the only alloy proven to provide protection in fresh water. Martyr brand marine anodes are a subsidiary of Canadian Metal (Pacific). Using advanced alloys and casting Martyr brand sacrifical anodes have gained an international reputation of superior quality.

Review: Perfect fit - All good
Review: Exact fit - Exactly what was on the boat previously!

## Features

- High-quality Martyr anodes are pressure diecast and manufactured to strict quality standards through an ISO 9001 Quality Management System
- Martyr anodes offer maximum protection by maintaining quality alloys, free from impurities like iron, which can compromise performance
- Three alloys available - Use Zinc (Martyr I) for salt water, Aluminum (Martyr II) for brackish water, or Magnesium (Martyr III) in fresh water.
- Use alternative anode alloys when changing water conditions
- Provides low cost cathodic protection of ocean-going vessels, structures and equipment constructed of iron, steel, aluminum, magnesium, and other metals

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B003E1UHMI |
| Brand Name | MARTYR |
| Customer Reviews | 4.8 4.8 out of 5 stars (72) |
| Global Trade Identification Number | 00628309127886 |
| Included Components | Magnesium Rudder Anode |
| Item Dimensions L x W x Thickness | 3.75"L x 2"W x 3.75"Th |
| Item Thickness | 0.25 Hundredths-Inches |
| Item Weight | 6.24 ounces |
| Manufacturer | Martyr Anodes |
| Material Type | Magnesium |
| Model Number | CMR03M |
| Number of Pieces | 1 |
| Part Number | CMR03M |
| Shape | Round |
| UPC | 628309127886 |
| Unit Count | 1.0 Count |

## Product Details

- **Brand:** MARTYR
- **Item Thickness:** 0.25 Hundredths-Inches
- **Material:** Magnesium
- **Product Dimensions:** 3.75"L x 2"W x 3.75"Th
- **Shape:** Round

## Images

![Anodes, CMR03M, Magnesium Rudder & Trim Tab Disc Anode (0.5 H x 3.75 OD x 0.34 ID) – Marine Boat Sacrificial Anode for Freshwater Corrosion Protection - Image 1](https://m.media-amazon.com/images/I/61Lj+7qEzWL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Perfect fit
*by J***E on April 11, 2025*

All good

### ⭐⭐⭐⭐⭐ Exact fit
*by L***E on March 25, 2025*

Exactly what was on the boat previously!

### ⭐⭐⭐⭐⭐ Perfect replacement for trim tab
*by M***N on May 6, 2024*

Bought this to replace the anodes on my trim tabs, the kit comes with 2 halves, so with some hardware one kit took care of both tabs

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*Product available on Desertcart Vanuatu*
*Store origin: VU*
*Last updated: 2026-05-05*