Marelux Sony a1II and A9III underwater housing for mirrorless cameras

Marelux Underwater Housing

Marelux Sony a1II/A9III Underwater Housing

A precision anodized aluminum housing built for serious Sony shooters who need reliable controls, secure port locking, and advanced flash/power options underwater.

For underwater shooters pushing the absolute limits of the Sony a1 II and a9 III, plastic or poly-carbonate options just won’t cut it. When you are operating at depth, you need absolute structural rigidity, tactile certainty, and an ecosystem built for precision optics. The anodized aluminum Marelux underwater housing (MX-A1II) delivers a robust, travel-ready system designed specifically to handle these blistering fast full-frame bodies.At Bluewater Photo, we have rigged and field-tested every major platform on the market.

One of the single greatest advantages we see with the Marelux lineup is their unified hardware approach. Unlike other premium brands where you have to juggle various sizes, every mirrorless marelux housing utilizes the robust, 5-inch Series 5 port platform. This means your ports and extension rings seamlessly swap across different camera bodies within the brand, dramatically simplifying your gear bag.

Uncompromising Features Engineered for the DeepThe Marelux MX-A1II isn't just a shell; it is an extension of your camera's high-speed capabilities. Built around a massive 125mm port diameter—the largest available on the market—installing or removing large-diameter lenses like the Sony GM series is smooth and effortless.

Flashfuel FF2100 Module: This patented, dual-purpose internal engine bridges the gap between lightning-fast strobe synchronization and critical camera power. It combines a highly responsive manual flash trigger (good for up to 300,000 pops on a single lithium cell) with a built-in 2100mAh power bank, pushing up to 30W of direct USB-C juice straight to your Sony camera battery while underwater.

Fail-Safe Dual Locking & Built-In Port Lock: A robust dual-lock housing latch system means it is virtually impossible to accidentally open a latch on a rolling dive deck or during a rough boat entry. Battery and card changes take seconds, and the integrated Series 5 port lock secures your extension ring safely with a definitive click.

Isolated Remote Shutter Capability: Built to work flawlessly alongside the Marelux Artemis 4500 RMT light, the housing features a patented optical receiving module with a wide 140° angle. You can easily trigger your shutter remotely from up to 10 meters away—perfect for skittish wildlife or complex studio pools.Intuitive, Cold-Water Ergonomics: Precision control placement puts critical Sony inputs like the AF-ON and Q Menu exactly where your thumbs naturally rest, easily manageable even when wearing thick drysuit gloves.

At Bluewater Photo, we have rigged, dive-tested, and pushed these camera bodies to their absolute limits. If you are still deciding between these two powerhouse systems check out our comprehensive Sony a1 II Underwater Review and our real-world Sony a9 III Underwater Review to see how their sensors and autofocus track fast-moving marine life in low-light environments.

Buyer Highlights

Best for: Sony a1 II and A9 III underwater photographers building a serious Marelux housing system.
Main advantage: Anodized aluminum construction, 100m depth rating, secure locks, and a compact control layout.
Compatibility note: Requires the correct Marelux Series 5 port, extension ring, lens gear, and lighting setup for your lens.
Differentiator: Flashfuel FF2100 combines manual flash triggering with a 2100mAh USB-C power bank option.
Tradeoff: Aluminum housings cost and weigh more than basic polycarbonate systems, but deliver better rigidity and long-term system confidence.

Quick Specs

MaterialAnodized aluminum alloy

Dimensions354mm W x 187mm H x 156mm D

Weight in Air3.30kg

Weight in Water220g

Depth Rating100m

Port MountMarelux Series 5

Flashfuel FF2100Manual flash trigger + 2100mAh power bank combo

USB-C OutputUp to 30W, 5–20V

Remote ShutterCompatible with Marelux Artemis 4500 RMT Light module system

Manual Trigger BatteryTwo CR2032 batteries

Key Features for Real Underwater Shooting

Dual locking system on Marelux Sony a1II and A9III underwater housing

Dual Locking System and Built-In Port Lock

A housing lock should be easy to operate on a dive deck, but hard to open by accident. Marelux uses a dual locking approach that takes little effort to close, opens quickly when you need battery access, and helps prevent accidental release during travel or boat handling.

Secure closure for demanding dive conditions
Fast access for battery or card changes
Built-in lock helps keep extension rings and ports safely in place
Useful for travel diving where gear is handled often

Flashfuel FF2100 Trigger and Camera Power Support

Patented Design: Tailored for underwater photography and high-speed shooting, combining flash triggering and camera power supply in a single compact device.

Ultra-durable Trigger Performance: Powered by a single CR123A 3 V lithium battery, it can handle up to 300,000 flash triggers before replacement.

Robust USB-C Power Output: Integrates a 2100 mAh rechargeable battery, offering up to 30 W output (5–20 V), capable of powering your camera directly.

Marelux Flashfuel FF2100 manual flash trigger and power bank module inside housing

Remote shutter module and quick release baseplate for Marelux Sony a1II and A9III underwater housing

Remote Shutter Capability and Sturdy Baseplate

With an invention patent, the Remote Shutter Module is designed to enhance underwater photography by providing remote control capabilities to remotely control the camera shutter release via Marelux's Artemis 4500 RMT Light (42703). It features an effective receiving distance of 10 meters and an optical signal receiving angle of 140 degrees, allowing for flexible positioning and reliable performance.

Remote camera shutter release when paired with compatible Marelux remote gear
10m effective receiving distance
140-degree optical signal receiving angle

Why Buy From Bluewater Photo?

Underwater housings are system purchases, not single-box purchases. Bluewater Photo helps confirm compatibility, choose ports and gears, match lighting, and avoid the expensive mistakes that happen when camera, lens, port, and strobe components are ordered separately without a system check.

Marelux has built a strong reputation among underwater photographers looking for durable aluminum housings, reliable controls, and a growing professional ecosystem.

Content reviewed by Bluewater Photo staff, recognized as the #1 online retailer specializing in underwater photography and scuba diving equipment, with real-world experience supporting, selling, and configuring underwater camera systems.

Ready to Build Your Sony Underwater System?

Expert support from underwater photographers.

Best Underwater Settings for the Sony a1II and A9III

Getting perfect tracking and exposure at depth requires specific camera configurations. Skip the trial-and-error on your first dive trip with our step-by-step optimization guides:

For a1 II Owners: Read our vetted Sony a1 II Underwater Settings guide to master your custom buttons and strobe sync.

4_dm1AN6G2M

For a9 III Owners: Learn how to maximize the global shutter with our Sony a9 III Underwater Settings breakdown.

yVdxL3gyCzw

Related Underwater Gear Categories:

Specifications

Build

Material: Anodized aluminum alloy
Dimensions: 354mm W x 187mm H x 156mm D
Weight in air: 3.30kg
Weight in water: 220g
Depth rating: 100m

Ports and Locking

Port mount: Marelux Series 5
Built-in port and extension ring lock
Dual locking housing closure system
Quick release baseplate

Flash Trigger and Power

Flashfuel FF2100: manual flash trigger + 2100mAh power bank combo
Flashfuel trigger battery: One CR123A 3V lithium battery
Flashfuel trigger performance: Up to 300,000 flash triggers
USB-C power output: Up to 30W, 5–20V
Manual flash trigger option: Up to 100,000 triggers on two CR2032 batteries

Remote Operation

Remote shutter module support
Works with Marelux Artemis 4500 RMT Light, model 42703
Effective receiving distance: 10 meters
Optical signal receiving angle: 140 degrees
Camera compatibility details: Compatibility varies by system — contact Bluewater Photo to confirm your setup

Weight: 5.00 LBS

Dimensions: 10.00 (in) × 9.00 (in) × 15.00 (in)

Brand: Marelux

Camera Type: Sony A1 II

FAQ

Does this housing fit the Sony a1 II and Sony A9 III?

This product is listed for the Sony a1II/A9III. Final compatibility should be confirmed with Bluewater Photo because camera controls, firmware behavior, and accessory configuration can vary.

Which port do I need?

The housing uses the Marelux Series 5 port mount. The correct port, extension ring, and lens gear depend on your exact lens, so use the Marelux port chart or contact Bluewater Photo for a system check.

Is the Flashfuel FF2100 a TTL trigger?

The Flashfuel FF2100 is described as a manual flash trigger and 2100mAh power bank combo. TTL compatibility is not listed here, so plan on manual optical strobe triggering unless your exact configuration is verified.

Can this housing power my camera underwater?

The Flashfuel FF2100 integrates a 2100mAh rechargeable battery with USB-C output up to 30W. Camera power support depends on your camera settings, cable configuration, and whether your camera accepts external USB-C power in the intended shooting mode.

What maintenance does this housing need?

Inspect and clean the main O-ring, port O-rings, and sealing surfaces before every dive day. Rinse the housing in fresh water after diving and work the controls while submerged to remove salt from buttons and shafts.

What accessories should I order with it?

Most buyers need a Series 5 port, extension ring, lens gear, fiber optic cables, arms, clamps, and strobes or video lights. Bluewater Photo can configure the complete system around your camera body and lens list.

How does Marelux compare to Nauticam?

Marelux is a strong choice for divers who want an aluminum housing, secure locks, and a growing accessory ecosystem at a competitive system value. Nauticam may be preferable if you already own Nauticam ports or want to stay inside that established ecosystem.

We offer lifetime support with all purchases.
Please call or email us with any questions; our knowledgeable staff would love to assist you.