Review: WalleFPV Naked DJI O4 Pro – Only 18g! The Upgrade We’ve Been Waiting For!

The DJI O4 Pro Air Unit is fantastic, but one major downside is its weight. At 33g, it’s not ideal for micro quads or builds that aim to stay under the 250g weight limit.

That’s why the “naked” DJI O4 Pro has been one of the most anticipated upgrade in the FPV hobby. A “naked O4 Pro” essentially removes the original housing and heatsink, replacing them with a minimal aluminium bracket, reducing weight by 42%!

After taking a closer look at the WalleFPV Naked O4 Pro, I have to say it’s highly engineered. It’s clear a lot of thought has gone into the design, and the level of weight saving is impressive. However, it does introduce a few trade-offs that you should consider before using it, which I’ll cover in this review.

New to the DJI FPV system?

Where to Buy

Get the WalleFPV Naked O4 Pro Air Unit from:

You can also just buy the upgrade kit and modify your own O4 Pro:

The kit comes with these accessories

• M1.5 hex screwdriver
• Phillips screwdriver
• A bag of spare screws
• Two micro 5.8GHz antennas

If you purchase the full naked O4 Air Unit, it will also include the original housing and antennas. There is also a 6-pin cable for connecting the Air Unit to the flight controller (not shown in the picture). This is the standard cable that comes with the original O4 Pro.

The Pros and Cons of Naked O4 Pro

Pros

Ultra lightweight

The original DJI O4 Pro weighs around 33g, while the Naked O4 Pro comes in at just under 19g — a 14g reduction. This significantly improves flight performance and efficiency of your FPV drone, making it ideal for micro quads, sub-250g builds, and long-range drones.

Drop-in compatibility

The Naked O4 Pro uses the same mounting pattern for both the camera and transmitter module as the original air unit, making it compatible with existing frames and BNF drones. For existing setups, it’s essentially a plug-and-play upgrade.

More compact design

It’s slightly smaller than the original, allowing it to fit into tighter builds.

Same functionality

You get the exact same features and performance as the original DJI O4 Pro.

Cons

Cooling is a major concern

From my testing, the Naked O4 Pro is much more prone to overheating without sufficient airflow. It’s not ideal for enclosed frames or ground vehicles where airflow is limited.

Reduced durability

Although the brackets are made from 6061 aerospace-grade aluminium (according to WalleFPV), the PCB is far more exposed compared to the stock housing. This makes it more vulnerable to crashes and environmental damage. You might want to consider adding conformal coating for water resistance: https://oscarliang.com/waterproofing-drone-electronics/

ND filter compatibility

The original DJI ND filters no longer fit. You’ll need to use WalleFPV’s custom ND filters. Alternatively, you can reinstall the original camera housing if you want to keep using DJI filters.

Warranty void

Modifying your DJI O4 Pro will void the DJI warranty.

Size & Weight Mesurements and Comparison

Weight Breakdown

You can also mix and match antennas or camera modules depending on your needs.

Dimensions

The mounting is essentially identical, so it’s compatible with existing O4 Pro builds.

The longer 150mm cable is great for 5-inch and long-range drones. A shorter 60mm cable is also available, which is ideal for micro builds (2-inch and smaller).

Build Details

Installing the Naked O4 Pro is a breeze.

With original O4 Pro, my Flywoo Explorer weighs 166g:

With the Naked O4 Pro it now weighs only 152g!

WalleFPV has gone to great lengths to reduce weight—even using aluminium screws to shave off every possible gram.

Left: Original housing screws; Right: Naked O4 Pro Screws

Connector is held securely using tiny Philip screws.

It’s this level of attention to detail that makes the weight reduction so impressive, but it also highlights the trade-off: durability and thermal performance take a hit.

Overheat Testing

With the heatsink removed, we expect the Air Unit to overheat more quickly—so let’s test it.

Test Conditions

• Ambient temperature: 20°C
• No airflow (indoor bench test)
• Quad armed (Air Unit transmits at full power 1200mW)
• Bitrate: 60Mbps
• VTX Onboard Recording: 4K 60fps

Results

Original O4 Pro

• Overheat warning: 2 minutes
• Air Unit Shutdown: Never (within the 10-minute test)

WalleFPV Naked O4 Pro

• Overheat warning: 40 seconds
• Air Unit Shutdown: 2 minutes

When the overheat warning appears, the Air Unit attempts to reduce temperature by:

• Stopping onboard recording
• Dropping bitrate to 30–40Mbps
• Reducing transmission power

If the temperature continues to rise, the Air Unit will eventually shut down to prevent hardware damage—resulting in complete loss of video signal.

xxx overheat warning image

Real-World Implications

Bench testing represents the worst-case scenario because there’s no airflow.

When you are flying:

• Airflow significantly improves cooling
• Overheating is less likely even without heatsink

This has been proven with the naked DJI O3 Air Unit which I tested extensively. As long as there’s decent airflow it shouldn’t be an issue.

However, the results clearly show that the Naked O4 Pro overheats much faster due to the lack of a heatsink. Thermal management becomes critical.

My Practical Advice

From my testing, here’s what I recommend:

• Use lower VTX power for short-range flying, or use Auto Power
• Avoid leaving the quad powered on the ground for too long, take off as soon as possible after plugging in the battery
• In hot weather, always do a short test flight nearby first, to make sure your naked O4 can handle it before flying too far away

ND Filters

Once you remove the original camera housing, the stock DJI ND filters are no longer compatible.

You’ll need WalleFPV’s dedicated filter set:

Included Filters

Even if you don’t use ND filters, I still recommend putting the UV filter on—it acts as a lens protector.

Further Reading: Why ND filters are beneficial to image quality: https://oscarliang.com/nd-filter-fpv/

Naked O4 Pro vs O4 Lite

Without any modifications, the O4 Pro is clearly superior in image quality.

But things change when you add a wide-angle lens to the O4 Lite. Check out my review here: https://oscarliang.com/flywoo-o4-wide-angle-lens-new/

But when it comes to weight, the O4 Lite no longer has the clear advantage over the Naked O4 Pro:

• O4 Lite + Wide Angle lens: 15g
• Naked O4 Pro: 19g

For micro quads (like the 1S Flywoo Firefly18), that 4g weight difference still makes a big difference.

And consider the price difference:

• O4 Lite + Wide Angle lens: roughly $170
• Naked O4 Pro (DIY): roughly $260

With that said, the O4 Lite simply cannot match the O4 Pro camera when it comes to image quality, which features a 1/1.3-inch sensor (better dynamic range and low light), 4K/120fps recording, a 155° ultra-wide-angle lens and 10-bit D-Log M color mode—all critical features the O4 Lite camera lacks.

How to Upgrade

If you want to convert your own O4 Pro, you can follow this guide: https://drive.google.com/file/d/1wmJ15Pm2PHmTLj2q3AZpOceW6Ngzxk88/view?usp=sharing

Conclusion

The WalleFPV Naked O4 Pro is exactly what many FPV pilots have been waiting for—a way to bring the full performance of the DJI O4 Pro into lightweight builds.

The ~14g weight reduction is massive, especially for sub-250g micro drones and long range builds. And the engineering behind this kit is genuinely impressive.

Buy the WalleFPV Naked O4 Pro Kit here:

However, this comes with real trade-offs:

• Significantly reduced cooling performance
• Increased fragility
• Loss of compatibility with original ND filters

From my experience, this upgrade makes the most sense if:

• You prioritize weight and performance
• You don’t crash a lot
• Your drone has decent airflow to the air unit

If you’re building a high-performance lightweight quad with DJI O4 Pro, this is easily one of the most impactful upgrades you can make. But if you’re flying in hot climates, your drone has an enclosed frame, or you crash a lot, you’ll need to be extra careful with this hack.