---
product_id: 23782678
title: "Martyr 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: "€ 65.78"
currency: EUR
in_stock: true
reviews_count: 8
category: "Martyr"
url: https://www.desertcart.gr/products/23782678-martyr-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode
store_origin: GR
region: Greece
---

# Magnesium alloy for freshwater ISO 9001 certified precision Impurity-free alloy protection Martyr 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:** € 65.78
**Availability:** ✅ In Stock

## Summary

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

## Quick Answers

- **What is this?** Martyr 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?** € 65.78 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.gr](https://www.desertcart.gr/products/23782678-martyr-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode)

## 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

- • **Pure Alloy, Pure Protection:** Crafted free from iron impurities to maximize corrosion resistance and extend vessel life.
- • **Trusted by Marine Pros Worldwide:** Martyr’s global reputation for quality means your boat’s rudder and trim tabs stay safeguarded season after season.
- • **Tailored for Freshwater Excellence:** Magnesium alloy specifically designed to deliver superior sacrificial protection in freshwater environments.
- • **Precision Engineered for Peak Performance:** Pressure diecast with ISO 9001 quality standards ensures unmatched durability and reliability.
- • **Versatile Alloy Options for Every Water Type:** Switch easily between Zinc, Aluminum, or Magnesium anodes to match your water conditions and optimize protection.

## Overview

The Martyr CMR03M Magnesium Rudder & Trim Tab Disc Anode is a precision pressure diecast sacrificial anode designed exclusively for freshwater corrosion protection. Manufactured under ISO 9001 standards, it features a high-purity magnesium alloy that outperforms alternatives by preventing iron contamination. Ideal for marine professionals seeking reliable, long-lasting protection for rudders and trim tabs, this anode is part of Martyr’s trusted lineup, offering tailored alloy options for all water types.

## 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 | MARTYR |
| Brand Name | MARTYR |
| Customer Reviews | 4.8 out of 5 stars 74 Reviews |
| 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 | 0.39 Pounds |
| Manufacturer | Martyr Anodes |
| Material | Magnesium |
| Material Type | Magnesium |
| Model Number | CMR03M |
| Number of Pieces | 1 |
| Part Number | CMR03M |
| Product Dimensions | 3.75"L x 2"W x 3.75"Th |
| 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

![Martyr 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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**Shop now:** [https://www.desertcart.gr/products/23782678-martyr-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode](https://www.desertcart.gr/products/23782678-martyr-anodes-cmr03m-magnesium-rudder-and-trim-tab-disc-anode)

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*Product available on Desertcart Greece*
*Store origin: GR*
*Last updated: 2026-07-11*