The Haylou Watch 4S was launched in late July 2025 as the brand's new smartwatch. It's aimed at those looking for a wearable that combines design and functionality for well-being. Has the manufacturer managed to ensure a flawless experience with this wearable? What are its strengths? I tested it and share the details in our review.
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HAYLOU Watch 4S GPS Smartwatch 1,43 inch HD AMOLED Display 5 Satellite GPS Positioning Plus 120 Workout Modes Sports Fitness Smart Watch
Project development and construction
The Haylou Watch 4S is one of the most exclusive wearables the brand has ever created. It features a circular case with a polished metal frame. It weighs approximately 62 grams, a bit heavy for its category, but not so much that it's uncomfortable to wear for hours on the wrist. The watch has two buttons on the right side. The top one is round and can be used as a rotating crown. The second, flatter button opens the list of fitness activities.
At the end of the base, near the left side, is the audio output. At the bottom are the magnetic charging pins and the sensors that monitor your health and workouts. This wearable device features a silicone main strap with a wavy texture. It offers a pleasant feeling of resistance and overall comfort. The combination of the accessory and the structure creates a very sophisticated look for everyday use. However, the package also includes an additional strap, less elegant but more sporty. In any case, it features a 22mm quick release so you can purchase additional third-party straps to create a personalized outfit.
Water resistance is 1 ATM. In other words, it only offers basic protection against liquids, not to mention that it doesn't have an IP rating that guarantees dust resistance. Inside the compact box, you'll find the watch with the wavy band already attached, a USB cable with magnetic charging pins, and the user manuals. The package also includes an additional smooth silicone strap for added lightness and a screen protector.
Screen and sound
The smartwatch features a 1,43-inch AMOLED display with 2.5D curved glass, giving it a more modern look. It also boasts a resolution of 466 x 466 pixels, offering decent definition for its category. This display promises a maximum brightness of up to 1.000 nits. In our tests, we confirmed that the wearable can be used without difficulty in well-lit spaces.
The manufacturer's choice of material allows for the Always-on Display, with digital or analog clock options. There are only five watch faces built into the wearable, with a library of over 200 new watch faces that can be installed via the app, which we'll discuss in more detail shortly. The Watch 4S also uses audio output for multiple functions. Not only does it support Bluetooth calls, but it can also play music from your smartphone's player or stream music like Spotify when connected to your phone.
However, don't expect an advanced experience. The power is only decent and can make it difficult to hear depending on ambient noise. The quality is also mediocre and average for smartwatches. However, calls are a different story, with the audio delivered being quite clear and allowing for conversations even in moderately noisy environments, and the person you're talking to can hear you without noticing your voice sounding tinny or muffled.
System and resources
This model features the proprietary Haylou operating system, already present in other models. It's quite streamlined and doesn't allow the installation of additional apps. Language localization also leaves something to be desired, with some words poorly translated into Italian. Despite this, we didn't experience any crashes, and navigation is pleasantly fluid.
The menus don't offer anything new. You'll find notifications at the bottom, with no option to respond directly from the watch; a shortcut bar on the left; customizable tabs with measurements and weather on the right; and buttons to access some tools at the top. One of the strong points is the GPS built into the dual-band chip, which helps monitor outdoor activity. There are also two built-in games to keep the user entertained, whether it's solving the 2048 problem or controlling the flight of the Young Bird.
The basic smartwatch features are present, such as a flashlight, local weather forecast, alarm with audible alert, stopwatch, timer, calculator, and calendar information. However, other adventure-oriented features, such as a compass, are missing. Connectivity is provided by Bluetooth 5.3, but this device does not have Wi-Fi, meaning the watch is heavily reliant on a smartphone. All functions can be managed via the Haylou Fun app, available for Android and iOS.
The app displays sleep logs, heart rate, workouts, and other metrics, as well as showing battery level and allowing you to install software updates. Those familiar with the brand's tool won't get lost accessing every feature, as navigation is very intuitive.
Health and physical activity
And what are the salient features of this device in the health and physical activity segments? Let's start with the former, without any major surprises. It monitors the user's heart rate, as well as blood oxygen saturation and stress levels through what it calls "pressure," but don't confuse it with standard blood pressure.
During manual measurement, we noticed a delay in the result, a phenomenon we've already seen with other recent Haylou models. We counted about 12-15 seconds before the recording was complete. This time could have been much faster. Sleep tracking fluctuated between days when the sleep count was accurate and others when the sleep time was added to the total hours. Furthermore, the watch itself provides little detail, meaning you need to constantly look at it to determine the exact period of deep, light, or REM sleep.
For workouts, the manufacturer offers over 120 sports modes, some easily accessible and others organized by category. In addition to the aforementioned GPS routes, they also monitor heart rate and calories burned through the smartwatch's sensors and algorithms. While the measurement proved accurate, we lacked more comprehensive exercise information, including the lack of post-workout monitoring to understand the user's recovery.
Battery
This smartwatch features a 400 mAh battery. The manufacturer promises up to 18 days of use in basic mode, with just the standard dial and sleep tracking, or up to 10 days in daily mode, which adds constant heart rate monitoring, 100 notifications per day, and 150 screen activations. We tested it with notifications, heart rate and blood oxygen saturation monitoring enabled, as well as sleep tracking. With this configuration, we lasted a total of 7 days. This doesn't quite meet the company's specifications, but we consider a full charge per week to be satisfactory.
Charging occurs via magnetic connectors on the base of the smartwatch. For this experiment, we used the included cable along with a 15W power adapter. With this setup, the Watch 4S took about 2 hours and 20 minutes to charge to 100%. We know the wait could have been shorter, as the brand itself has released watches with the same battery life that charge more quickly, such as the Solar Ultra.
Final houghts
The Haylou Watch 4S is designed for those who want a sophisticated watch, suitable for both everyday use and business environments, and with a battery that lasts a week or more of constant use. The high-quality display is one of its strong points, as it doesn't disappoint in terms of size or visibility in sunny environments. Not to mention the fact that it still offers good overall image definition. The audio also scores highly, more for its features than its quality per se.
HAYLOU Watch 4S GPS Smartwatch 1,43 inch HD AMOLED Display 5 Satellite GPS Positioning Plus 120 Workout Modes Sports Fitness Smart Watch
Another difference with this model is the number of accessories included in the package, which include not only the basic ones but also an additional strap and a screen protector. Downsides include system translation issues, a delay in manual health measurements, and inaccurate sleep tracking. Not to mention the water resistance, which could be improved. That said, considering the price, it's a product I recommend.
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