WOLFBOX G840S 12-Inch 4K Mirror Dash Cam: features, specs and who it suits

The WOLFBOX G840S is a mirror dash cam: a 12-inch screen that sits over the car's existing rear-view mirror and combines a front camera, a rear camera and a recorder in one unit. It is meant for drivers who want a wider, clearer view behind the vehicle and a continuous record of the road ahead. Here is what its main specs mean in practice.

Two cameras, two resolutions

The front camera records at 4K (2160p), while the rear camera records at 1080p. In general, higher resolution means more detail when you replay footage, such as signs and the shape of other vehicles, though lighting and lens quality matter as much as the pixel count. WOLFBOX says the front lens covers 170° and the rear lens 140°, and that the wider view helps reduce blind spots when driving and reversing.

A larger mirror-style screen

The 12-inch display is described as offering about 1.5 times the viewing area of a standard mirror. A split-screen function shows both camera feeds at once, and the screen has a 2.5D curved glass edge so it blends with the interior. Because the screen replaces the view in the mirror, a camera-based image can be clearer than a mirror when the rear window is crowded with passengers or cargo. It also takes a moment to get used to, since you are looking at a screen rather than a reflection.

Night and difficult light

WOLFBOX lists a low-reflectivity LCD to cut daytime glare, WDR and HDR processing to balance bright and dark areas in the same scene, and a six-element glass lens paired with what it calls a professional-grade sensor. WDR (wide dynamic range) and HDR typically work by combining different exposures, which helps in tunnel exits, headlight glare and low sun. Results at night still depend on the street lighting and the windscreen's condition.

GPS and playback

An external GPS antenna is included. It shows real-time location data on the unit, and recordings can be played back with the route information. GPS data is also useful for noting speed and position in footage you look back at later.

Parking monitor and loop recording

Loop recording overwrites the oldest footage when the card is full, so the camera keeps recording without manual clearing. A 24-hour parking monitor uses a time-lapse mode that records at a low frame rate to conserve power and storage. The listing states that a hardwire kit is required for parking monitoring, since the camera needs a permanent power feed from the car's fuse box. A G-sensor is listed too, which typically locks a recording when it detects a sudden impact.

Power, storage and fit

The unit has a USB-C power port, which WOLFBOX says avoids restart and overheating problems. A 32GB card is included. At 4K, a card of that size holds a limited amount of footage before looping, so many owners choose a larger high-endurance card. The mirror measures about 11.9 x 2.8 x 0.7 inches and weighs 1.8 lb.

Who it suits

It suits drivers of cars and trucks who want one device for front and rear recording and a bigger rear view, and those who want GPS data attached to their footage. It is less suited to anyone who prefers a plain mirror or finds a screen distracting.

What to check before you buy

• Mounting: confirm that the clip-on mount fits the shape of your existing mirror and that the screen doesn't block your view.
• Rear camera cable: check the cable length against the length of your vehicle, especially a truck, and how you plan to route it.
• Parking mode: if you want it, allow time or a professional for the hardwire kit and check what your car's fuse box allows.
• Storage: decide whether the included card is enough, and what card sizes the unit supports.
• Local rules: check the rules in your area on windscreen-mounted devices and on recording.
• What's in the box: the listing mentions the card and GPS antenna; confirm the accessories you expect.

The short version

• A 12-inch mirror dash cam with a 4K front camera and a 1080p rear camera.
• 170° front and 140° rear lenses, with split-screen display.
• WDR, HDR and a low-reflectivity screen for difficult light.
• External GPS, loop recording, G-sensor and a time-lapse parking monitor that needs a hardwire kit.
• USB-C power and a 32GB card included.

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