On June 28, 2021, I received the COLMI P10, which I bought from abroad for 22€ (equivalent in USD). It is cheaper than what is currently available in Greece, but the order took about 1.5 months to arrive - I wasn't in a hurry, though - and according to the order tracking, the delay was due to Greek customs, if that is true, if we remove this delay time and leave the rest, the watch arrived quickly.

The review was edited on May 3, 2022.

First impressions (the watch will be judged over time, with updates): it seems "honest" for its cost. Visually, its square case reminds me a bit of a vintage CASIO digital watch, which I like (in fact, I created a face that says CASIO, see photo). Although it is my first smartwatch, connecting it to my phone through the GloryFit app was easy, even though I am a beginner.

It is a very lightweight watch, it looks and doesn't look sturdy for its shape and form... time will tell... Almost a year later (May 3, 2022), it is still working fine, and I wear it daily due to its multiple functions.

The touch screen seems to respond satisfactorily, but I am a beginner with smartwatches, so I don't have any comparison experience.

In reality, it is a sports watch/fitness tracker: it has many functions for tracking sports activities, sleep, heart rate, and blood pressure. It also has call notifications (from your mobile phone) and message notifications - you can choose from which app (e.g. WhatsApp, Viber, etc.) you want to receive notifications on the watch.

It also has the ability to find your phone within a distance of up to 5 meters, meaning you can select "find mobile" and your phone will ring, as if someone is calling (useful if you have misplaced your phone and it is on silent mode, and you are looking for it).

Regarding messages, it only displays them if they are written in English (Greeklish) - if they are written in Greek, they appear as "gibberish/Chinese". This is a disadvantage. Another related disadvantage is that it only displays messages up to a certain length (if they are long messages, it roughly displays 1/3 of it) and you cannot open and read the entire message by tapping on it. Additionally, the letters are so small that even with my glasses, I couldn't read them properly due to my slight presbyopia.

Therefore, when it comes to messages, it has significant drawbacks, and practically, it simply notifies you that you have a message, so you can view it properly on your smartphone. The font size cannot be increased anywhere in the settings, either on the watch itself or in the smartphone app, so it remains small.

The watch, without increasing the contrast that you can adjust, at the maximum level, which I had set at about halfway, cannot be seen in the sun unless you shade it with your palm. However, as I mentioned, I could increase the contrast, but I didn't.

The watch has a stopwatch, countdown timer, and alarm, but while the last two require sound, the watch does not have a beeper (which makes beeping sounds). So how does it notify you when the time is up? Through vibration. The vibration is just a vibration. If you are awake and want to set a reminder for something, it works fine, you can feel and be notified by the vibration. However, if you have set an alarm and are asleep, it is impossible to wake up from the vibration alone. But even if it had a beeper (like digital watches such as CASIO, etc.), does anyone wake up from the beeping sound? I don't think it's mainly for notifications while you're awake.

By default, the watch has only 3 faces, although the GloryFit app has other faces (not too many) that you can download, which I tried, but there is another disadvantage: downloading a new face (the fourth one, after the 3 that the COMLI P10 has) takes quite a long time (about 5 minutes if successful, but there are also unsuccessful attempts that lose the Bluetooth connection and waste time - it may have been slow for me because of the not-so-good smartphone I have. It may take half a minute for someone else with a good smartphone to download the new face.
If you then try to add a 5th face, after adding it, the watch loses the fourth one you had. In other words, the watch can only store 4 faces in its memory - the 3 "factory" ones, plus one downloaded from GloryFit. You can't have more than 4 faces on the watch (the three "factory" ones, plus one downloaded - always the last one).
In the GloryFit app on the smartphone, there is also a tab where you can create your own face by uploading an image (e.g. a photo) and it only displays digital time (no option for hands), and you can choose the color so that it contrasts and is visible based on the chosen image. In the image I provided, I created a personal face (simple though), essentially making a black square in Paint (Windows) and adding the CASIO logo in white letters at the right spot.

The watch is IP67, which means that it is factory suitable only for regular water use. I don't know if it will be waterproof for swimming, although it has a swimming mode for the various activities it tracks. You can monitor the swimming activity or other sports/modes it has, such as running, walking, etc., through the GloryFit app on your mobile.

I sent a specific question with three sub-questions about water resistance to the COLMI company, and they replied within 2 business days, stating the following:
Question: Can I use the COLMI P10 for
1. swimming in the sea - not diving or deep dives, only surface swimming?
2. swimming in a chlorinated pool (but not saltwater)?
3. Can I wear it when taking a shower, with lukewarm water temperature (not too hot, not too cold), and with not too high water pressure?

The answers I received from the Chinese manufacturers were:
1. It is better not to swim in the sea because seawater will corrode the watch over time (in other words, increased chances of it getting damaged over time).
2. You can swim in a pool.
3. You should not wear it when taking a hot shower (so even worse if it is very hot), but you can wear it when taking a cold shower.
[Since most people take somewhat warm showers, it is better not to wear it, obviously frequent exposure to water with high temperatures can damage the waterproof seals, and the watch may eventually "die" from water damage.]

Battery: It charges with a magnetic cable that attaches to the base of the watch.
How long does the battery last?
The manufacturer says one week, but with the first charge, and without intense use (such as continuous measurements during exercise), it lasted 4 days. Obviously, it also depends on usage, the more intense the use, the more it will consume battery life. Over time, it will be like mobile phones, when it's new it will last for about 4 days, as it ages it will start to decline until it reaches a point where it may need to be charged daily. One year later (03.05.2022), the battery still lasts for 4 days, with moderate use of the smartwatch.

I also note something else about the battery. The indication on the watch is not as accurate as on smartphones, which means that it may visually show 1/4 but last much less (e.g. only a couple of hours). So if you don't want to run out of battery, it is good to charge it up to 100% as soon as it drops below 50%. It might be good to have a power bank with you as well.

Overall satisfied with a beautiful and possibly rugged fitness, health smartwatch, costing 22€ - it would leave me satisfied if it cost up to 30 euros, not more. So far (03.05.2022), it works great.

[Edit 03.08.2021] Its indications should not be particularly accurate. As for sleep tracking, which shows the phases of Deep sleep and Light Sleep, I have noticed that just before I wake up, when I wake up with an alarm, I remember in some cases the dream I had, while when I look at the sleep graph in the GloryFit app, which takes data from the smartwatch, it shows that I was in Light Sleep before waking up. I think dreams occur during deep sleep, so the indications may not be accurate, but I don't know how accurate the indications are on other more expensive smartwatches. I say this because as I researched it, they use the same technology, with a sensor that detects movement. Regarding sleep tracking again, once while I was lying down to sleep, around 2 o'clock, I was listening to the radio from my smartphone, and I fell asleep around 4:00. In the morning when I checked the sleep recording in the GloryFit app, it showed that I had started sleeping at 2 o'clock, even though, as I said, I fell asleep at 4:00. Obviously, because I was lying down and not moving, I "tricked" the sensor, which thought that due to the lack of movement, I had fallen asleep.

Also, its blood pressure monitor always shows 120 over 80, so either I always have stable blood pressure (which I don't know because I have never measured it with a precision instrument) or its measurement is completely inaccurate (more likely).

It is waterproof, as the manufacturers told me. I take showers with it, but with cold water, but now it's summer, so the cold water is actually slightly lukewarm. I don't wear it in the sea, but it handles water from the shower and faucets normally and with a strong flow. It has coped well. In the past winter, when I took showers with hot water, I took it off.

[Edit 21.12.2022] The strap broke, and I had to replace it. It broke after about one and a half years, which was expected. After all, I wore it all summer, and the sun "burns" these straps (plastic, rubber). The new rubber strap looks good, but it cost 20 euros, almost as much as the whole watch. But it is a necessary cost that you cannot avoid - well, if I had searched, I might have found a cheaper strap - but I didn't bother to do it.
The smartwatch has been working great all this time, everything is fine, satisfied. I'm also adding new photos with the new strap.