Casio is a Japanese company founded in 1946 by Tadao Kashio. Accompanying the progress of the company allowed in 1983, to create the first watch, the G-shock series, which launched the production, recognized and coveted worldwide line, indestructible timepieces. Japanese engineers, taught by years of experience, made every effort to ensure that their series of watches, was resistant to impacts and shocks, its mechanism was accurate and durable, and the appearance of the G-shock series watch was highly absorbing. The letter G here stands for gravity, strongly alluding to the watch's resistance to falls from great distances. Personally, I own 3 Casio watches from the G-shock series and am extremely satisfied with them. The hero of this review will be the red Casio G-shock GA-100B-4AER. Let me start with the appearance. The watch, thanks to its red color scheme, which is very important, matte, looks insane on the hand. Much better than in the pictures on the net. It catches the eye and positively surprises friends. I have to mention that despite its sizable size, the watch wears comfortably and conveniently. A solid buckle (two rows of holes), and a comfortable and durable strap, provide a sense of security and awareness of wearing a high-end product. However, the large envelope, with a large dial, is the greatest asset of this G-shock. Although there is a lot going on here, everything is easy to read and very clear. As this model is analog-digital, we can read the time, using the hands, or in the left screen, digitally - in the same place we can switch, between showing the time (in 12-hour or 24-hour mode), or set to permanently display the date. The right screen displays the current day of the week and seconds. At the top we have a pointer, with an accompanying window, which are used to show our average speed. When we finish a run, in addition to the time, we find out what speed we ran at on average. A circular window tells us what modes are active - whether we have the alarm, sleep alarm, full hour signal and the automatic dial backlight function on. I love the solutions included in this model, because you can see everything as if it were on. Let's move on to the modes and capabilities of the watch. The time, as I already mentioned, can be displayed in 12 or 24-hour mode. There is also a useful DST function - summer and winter time mode. When winter time occurs, we don't have to manually adjust the watch, we just hold down the button and the watch sets the time itself, displaying the correct time. For athletes, there is an advanced stopwatch with an accuracy of 1/1000th of a second, with interval and lap modes, and the aforementioned speed measurement - incredible fun to use this function. The timer, which is a downward countdown, with an option to automatically repeat the countdown, will come in handy in workouts, but also when cooking or baking - a very practical function for forgetful people. The next mode is world time. This model displays the time in 48 cities around the world. This can prove useful in many professions, when we have family abroad, or when traveling. There is a way, (by holding down two buttons), to instantly swap the main time display of our place of residence, with the time of another time zone, for example, to which we are just traveling. The display of these times, will swap places, without the need for settings. The last mode is alarms, and here it is also good. We have 5 alarms at our disposal - 4 daily alarms and 1 sleep alarm, as well as the ability to enable the SIG function, which is a short beep each time at an equal time. I love this function, because when absorbed in some activity, I can better control the time. The hour dots are coated with a luminescent substance, so that they glow in the dark after contact with a light source. Unfortunately, the manufacturer did not cover the hands with this substance, so in the dark we will not read the time using this solution - but in my opinion, this is an insignificant detail. Speaking of backlighting, an amber-colored LED, located at the bottom of the dial, is responsible for it. It does not strongly illuminate the entire dial face, while for reading the time in the dark it is completely sufficient, creating a beautiful atmosphere with its amber light. It is possible to choose the length of the backlighting time - 1.5 or 3 seconds. This timepiece has received yet a very cool option on this subject. By holding down the appropriate button, we can activate the automatic backlighting function. When we turn our hand with the watch towards our face, the backlight will turn on by itself - very useful when we do something in the dark with our hands busy. Rather a fiddly feature, but it's there. Of course, in a watch from this legendary series, no one will be surprised by the increased resistance to shocks, falls and impacts, the highly resistant mineral glass, which is hidden inside the bezel, and the watch's water resistance of 200 meters, which allows for specific water sports. Interestingly, this watch has a magnetic field protection function. The whole thing is completed, the precise quartz mechanism, which drives the watch, with an automatic calendar and a warranty system of 3 + 3 years. As far as I'm concerned, it's great value for money. I've owned it for over 2 years now, and despite daily use, in a wide variety of conditions, it looks and performs great. If you're looking for a really decent and durable watch, with an interesting and eye-catching design and lots of practical functions, you couldn't have come to a better place. Casio G-shock GA-100B-4AER is a solid companion for very long years.