The striking Amazfit T-Rex Pro offers many settings and functions at a good price
Housing and equipment - housing tested according to military standard
At first glance, the T-Rex Pro looks bulky, which is also suggested by the name. That's why you're surprised at how light it is when you pick it up. At 46 g (~1.6 oz, without strap), it weighs less than the Huawei Watch GT 2 Pro (52 g/~1.8 oz) with roughly the same case diameter. Admittedly, Huawei also used metal in the latter. Amazfit was thrifty and only coated the polycarbonate casing's bezel with a hint of metal via a spraying process.
However, the metallic look suits the smartwatch well, which has passed 15 endurance tests according to military standard MIL-STD-810G. In detail, the shock-resistant watch can withstand temperatures between -40 and +70 degrees Celsius (~ -40 and +158 degrees Fahrenheit) as well as ice and freezing rain. It must also be able to survive situations in which it is exposed to moisture for up to 240 hours or salt spray for up to 96 hours. In addition, the case is water resistant up to 10 ATM.
For the band, Amazfit has opted for silicone rather than the more robust Flurelastomer material. Grooves on the inside as well as many recesses for the buckle's spine are supposed to minimize the sweat that develops under the band during an active workout. In practice, hardly any moisture actually collected there during sports. However, the connection of the 22 mm (~0.87 in) wide strap is atypical, and there is also no quick-release buckle, which many watches now have.
The AMOLED regulates its brightness with the help of a sensor and was easy to read outdoors in the test. When navigating, the T-Rex Pro connects to GPS and one of the three satellite systems Galileo, GLONASS or Beidou.
Other sensors include a geomagnetic sensor, accelerometer, gyroscope, barometer, and a PPG sensor for measuring heart rate and oxygen saturation. NFC, speakers or a microphone are not on board.
Setup and operation - Zepp app with many options
The T-Rex Pro connects to both the iPhone and an Android smartphone. The test was performed with an iPhone 12 Pro. The associated app used to be called Amazfit app and is now called Zepp app. Huami, the company behind the Amazfit brand, bought central areas of the Californian Zepp International more than two years ago and is increasingly using its name.
The app is used to configure notifications and health monitoring. Still existing weaknesses in the translation include Asian characters as well as a term that is probably wrong: You can supposedly activate the all-day blood pressure measurement in the app. However, the T-Rex Pro does not measure this to our knowledge. Since the option concerns stress analysis, it probably means recording heart rate variability here.
The 15 preloaded watch faces can be supplemented with more via the app. Compared with wearables from Huawei or Xiaomi, the offer is comparatively thin. Some of the customizable complications show the humidity or the times of sunrise and sunset on request. The watch has to be connected to the smartphone to update them.
The display is activated when the arm is lifted or one of the four side buttons is pressed, but not by tapping the display. Some operating steps can be accessed via gesture as well as via a key. For example, a vertical gesture downwards opens the access menu and also the upper left button. In contrast, only a vertical gesture to the right opens the notifications on the screen. The training app is assigned to the upper right button by default, but you can personalize it. The lower right button or a swipe gesture to the left opens the app overview. The lower left button or a vertical gesture upwards opens the widget list.
Widgets do not fill the entire screen on the smartwatch like on most smartwatches, but form a list that can be scrolled through with the two left buttons. Tapping on a widget or selecting it with the upper right button opens the corresponding app.
Telephony and notifications
The T-Rex Pro does not have a voice assistant. Incoming calls can be rejected or muted. Emojis in messages from social networks are only partially displayed and there are no missing symbols otherwise. The screen on the right shows the same message for comparison on a smartwatch with WearOS (TicWatch Pro 3)
Health and fitness - Manual measurement of oxygen saturation
The smartwatch measures the heart rate and the body's stress response around the clock if desired. The intervals between the heart rate measurements range from 1 to 30 minutes, depending on the setting. Falling below or exceeding previously set pulse limits triggers a warning.
The T-Rex Pro only measures oxygen saturation manually, and not automatically at night. According to the manufacturer, the tracker detects when the user is exposed to major changes in altitude and then reminds them to check their oxygen saturation. We were not able to verify this in the test.
In addition, like other fitness trackers, the T-Rex Pro also counts the number of steps taken and determines the distance and calorie burn from that. The dashboard on the smartphone brings all analyses together.
The Amazfit smartwatch records both nighttime sleep and a power nap during the day. The sleep log can only be viewed in the app. It evaluates the sleep quality in general and the proportional ratio of the sleep phases. Amazfit supplements the course of the heart rate in the recording of the sleep phases, but without numerical values.
Evaluation of physiological activity according to PAI
In addition to the aforementioned activity tracking of steps, distance, and calories burned, Amazfit evaluates personal physiological activity using PAI algorithms. PAI stands for Personal Activity Intelligence and takes into account data collected daily, such as heart rate, as well as data from the last training recordings.
The current training status and the recommended recovery time, which are also derived from past workouts, can also be read permanently and outside the last training log via the app or the "Training Status" widget.
Those who exercise a lot or actively do sports thus contribute to a higher PAI value. According to a Norwegian study, people with a high PAI value suffer less frequently from high blood pressure, heart disease and type 2 diabetes.
Compared to its predecessor, the Amazfit T-Rex presented at CES 2020, the successor offers some added value in the area of workout and training. These include, as mentioned earlier, barometric sensor for altitude profiles, tracking via 4 instead of 2 satellite navigation systems, and an increase in water resistance to 10 instead of 5 ATM.
The T-Rex pro makes a leap especially in the supported workouts, which now include over 100 compared to only 14 on the predecessor
You can activate automatic recognition individually for outdoor running, treadmill, walking, indoor walking, outdoor cycling, cross training, rowing machine and pool swimming. In addition, the sensitivity with which the smartwatch reacts to the activity of its wearer can be set, and whether it automatically records the detected workout or only after feedback from the user. In this way, Huami/Zepp combines the approach of Huawei, whose wearables initially only output a message that has to be acknowledged, and Fitbit, which automatically starts recording upon recognition.
When running, a "Virtual Rabbit" can take over the role of a virtual training partner whose speed you want to beat. If you specify a target stride rate, the fitness tracker vibrates in a matching beat pattern.
For many sports, the data display can be adjusted via the app and a 3D mode can be activated for trail running, which combines the 2D distance with the altitude changes. The calculation of the maximum oxygen uptake VO2max (only when running outdoors) and the training analysis are based on the Firstbeat algorithms.
Not tested, but according to the manufacturer, on board are the detection of swimming style, training length and frequency as well as SWOLF determination during swimming.
Amazfit specifies the runtime of the 390 mAh battery for typical use with up to 18 days when the always-on display is disabled. With the always-on display enabled, the test lasted just under 10 days with very little use, and only 3.5 days with heavy use with GPS-supported workouts and minute-by-minute heart rate measurement.
If you insist on the permanent display, at least during the day, you can set a schedule for the always-on display as well as activate it via gesture and increase the interval for heart rate measurement to save the battery.
The smartwatch needs 1 hour and 20 minutes to charge with a remaining capacity of 5%.
The robust T-Rex Pro left a good impression in the test, and the many years of development experience of Huami and especially Zepp come into play.
For example, while the first smartwatch from OnePlus still has some gaps, Amazfit is brimming with settings, from display management to measurement intervals and warning limits for health monitoring to options for sports. The energy management can also be influenced via many of them.
Athletes will hardly find another smartwatch with a customizable training display for less than €200 (~$239).
It has a lot to offer athletes in particular and meets the demands of a touring smartwatch much better than its predecessor.
However, those who are not interested in the T-Rex Pro for sporty reasons or because of its striking looks should check whether they prefer other wearables offering a larger range of watch faces and full-screen widget presentation.
Price and availability
Amazfit delivers the T-Rex Pro in Meteorite Black, Desert Grey, and Steel Blue, and the price has barely dropped below the MSRP of 169 Euros (~$202) at the moment. You can get it from online retailers like Amazon or directly from the manufacturer.