Giantz Universal Car Digital GPS Speedometer HUD Display Overspeed Warning Alarm

The description says this head-up display suits all cars and trucks, and the reason sits on the same page: the only thing it connects to is a cigarette lighter. It is powered by an included USB lead, and every figure it throws onto the glass — speed, distance, driving time, direction, altitude, satellite count — it works out from GPS rather than from the vehicle. The one number it takes from the car is battery voltage, and that arrives down the power lead too.

Neither display behind the buy button is the one described

The choice offered is a 65mm Display or a 90mm Display (2 Modes). The description gives one screen, a digital multi-colour LCD at 2.2inch, and one mode count, four display mode interfaces. Neither 65mm nor 90mm turns up on the listing at any point, and nor does two modes. Whichever of the two you pick, the specification underneath is not measuring it. No figure here has been converted, reconciled or chosen between to make the two agree.

An alarm with a volume and a span

The overspeed alarm is the best-specified thing on this page. It covers 0-200Km/hr, it sounds at 30dB(A) or more, and the units switch between MPH and KPH. What is missing is the speed at which it actually goes off, and whether that is something you set. Missing with it is any accuracy figure for the reading itself — no tolerance, no calibration and nothing saying how many satellites have to be found before the number on the glass means anything.

Key features

• Projects onto the windscreen: the unit sits on the dash and throws the reading into your line of sight.
• Runs off the lighter socket: a cigarette lighter USB cable is included and is the device's only connection to the vehicle.
• Speed from satellites: the reading is GPS-derived, which is why the page can claim it suits every car and truck.
• A long list on the glass: driving speed, satellite number, driving time, distance, direction, clock, altitude and battery voltage, with speed-up and brake tests after them and the list left open.
• Two alarms: an over-speed alarm and a low-voltage alarm, both named in the specification block.
• Eight brightness steps: the display adjusts across eight levels for day and night.
• Four display modes: the description offers a multifunction layout or a simple one.

Specifications

• Screen size as described: 2.2inch
• Size of the unit itself: 7x7x4.5cm
• Voltage it will run on: 9V-16Vdc, drawing 12Vdc/400mA
• Alarm speed range: 0-200Km/hr
• Alarm loudness: 30dB(A) or greater
• Length of the power lead: 230cm
• Shell and colour: plastic, black
• Four lines in the pack block: the display, the cable, a non-slip mat and an instruction manual

What the page never addresses

• Where a dash-mounted device may legally sit in an Australian vehicle goes unaddressed, as does the driver's field of view.
• Nothing mentions a reflective film, and nothing about double images on glass that has none.
• Accuracy is never quantified and calibration is never mentioned, on an instrument sold for keeping you under a limit.
• The entire method of holding it down is one line in the contents list — a non-slip mat — and the mat is never described, sized or explained.
• No satellite standard, no fix time and no antenna detail, though satellite number is one of the things the screen shows.
• No weight, and no country of origin.
• The description ends by claiming a twelve-month warranty and says nothing further: no conditions, no exclusions, no one identified as standing behind it. We relay that it is claimed, not the promise itself.
• Every measurement here stands unqualified. Giantz publishes no allowance sentence on the page, and we have not estimated one on its behalf.

Taken as a satellite instrument that happens to live on a dashboard, this does what the description says and asks nothing of the car beyond power. Taken as the display you selected at the buy button, the page in front of you is measuring something else.