Martyr CMX03M Magnesium Streamline Shaft Anode – 1" Shaft | Stainless Allen Screw | Freshwater
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Martyr CMX03M Magnesium Streamline Shaft Anode
Protect your 1" prop shaft in freshwater with this precision-cast magnesium streamline shaft anode. Magnesium is the correct sacrificial metal for freshwater use — it has a more active electrochemical potential than zinc or aluminum, making it the only material that provides effective galvanic protection in low-conductivity freshwater environments where zinc and aluminum anodes go passive and stop working.
The low-drag, hydrodynamic profile minimizes water resistance while the stainless steel Allen head screw locks the anode firmly in place — no rattling, no spinning, no surprises mid-season.
Compatible Applications
- 1" (25mm) diameter prop shafts
- Freshwater use only (lakes, rivers, reservoirs)
- Inboard and inboard/outboard (I/O) vessels
- Replaces OEM shaft anodes on most standard 1" shaft configurations
Specifications
- Part Number: CMX03M
- SKU: 194-CMX03M
- Material: Magnesium alloy (sacrificial)
- Shaft Diameter: 1" (25mm)
- Fastener: Stainless steel Allen head screw
- Profile: Streamlined / hydrodynamic
- Best For: Freshwater only
- Weight: ~140 g
Parts Desk Insights
The CMX03M is the correct choice for any 1" shaft running in freshwater. This is one of the most common anode mistakes we see — boaters in freshwater lakes install zinc anodes and wonder why their running gear is still corroding. Zinc simply doesn’t work in freshwater; it passivates and provides little to no protection. Magnesium is the right metal for the job.
If you operate in saltwater or brackish water, see the CMX03 Zinc version for saltwater or the CMX03AL Aluminum version for saltwater and brackish conditions.
Also available in adjacent sizes: CMX02M – 7/8" Magnesium | CMX04M – 1-1/8" Magnesium
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.