Cat Phones  - Cat Phones S41

Cat Phones

Cat Phones S41: a smartphone as solid as it is indestructible

Aprox. 569€ - see price -

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With this S41, Caterpillar is once again showing off its expertise in rugged smartphones. The S41 indeed delivers convincing performance, despite some regrettable weaknesses.

Our review


The small world of the rugged smartphone continues to grow, and Caterpillar continues to offer interesting "site phones". After its top-of-the-range model - the Cat S60, a real Swiss army knife even including a thermal camera! -, here is the S41. With its rubber shell, the smartphone wants to be ultra-resistant. It is also presented as a terminal with the most solid autonomy.

The S41 can be found at € 450 in all the shops. It therefore comes to compete with other rugged phones like the Crosscall Trekker X3.


Ergonomics and design

With its 218 g, the S41 is certified IP68 and MIL-STD-810G, a standard of military protection. This means that this S41 will be able to survive situations that would make its colleagues tremble. It thus withstands repetitive drops of 1.8 m on concrete. It is also waterproof and can remain submerged up to 2 m deep for 1 hour. Neither dust nor extreme temperatures make it cough.

Obviously, this robustness comes at a price: ergonomics. Suffice to say at the outset, the terminal is impressive. With its rubber shell, it is not likely to slip from your hands. Its physical buttons at the bottom of the screen, confusing at first, turn out to be rather pleasant. The side buttons, they, if well located, are not really distinguished from the bumpy shell. At the time of going to seek them, one thus finds oneself sometimes to check if one is well above before pressing.

The S41 is capable of accommodating two nano SIM, but also a microSD card in order to expand its internal memory, limited to 32 GB.

Ergonomics and design


The S41 is equipped with a 5-inch (12.7 cm) LCD panel with a 16: 9 ratio. Displaying 1,080 x 1,920 px and with a good resolution (481 ppi), this screen occupies "only" 60% of the front of the smartphone - a value rather usual in the world of rugged phones.

Overall, the slab of the S41 is far from bad. It will however be necessary to take a tour of the parameters to adjust it to your liking. Because two settings with different benefits are available to the user. The first is Standard mode, activated by default in the factory configuration. In this mode, the panel has a very pleasant maximum brightness in full sun, with a peak at 651 cd / m² and a color temperature set at 6.977 K, very close to the ideal value at 6,500 K; however it is on the side of the average delta E that the slab sins a little: it goes up to 5, a rather high value.

By delving into the settings, you can, if desired, switch to User mode. This done, you will have control over the color temperature. By decreasing it, you will be able to reach a temperature of 6,574 K, combined with an average delta E at 3.8, a guarantee of better color fidelity (despite a clear drift on bright blue). However, this will be at the expense of the maximum brightness slightly revised downwards, capping at 590 cd / m². Lighting always of very good quality, that said.

To set the smartphone in User mode as described above, go to the settings, then click on Display, then MiraVision. Then open the side panel and change the Picture mode. Once in User mode, the different settings of the side panel will be available and you will only have to adjust the color temperature as in the screenshot below.

Whatever mode you choose, the contrast ratio offered by the panel remains relatively low, at 929: 1. Just as limited, the minimum screen brightness fluctuates between 25 cd / m² in standard mode and 21 cd / m² with the settings chosen in User mode . Two values anyway too high for one to be able to comfortably use the smartphone at night without tiring the retina. A problem may be harmless for a sedentary smartphone, but which takes another magnitude when it is a terminal cut for those who sleep under the stars, far from light pollution.

Finally, the screen is fishing in terms of its reactivity. The tactile delay is significant (130 ms) and the afterglow time rather high (21 ms). However, despite its waterproofness, the slab does not suffer from high reflectance, since it remains at 9%, a very good value.



Under its shell, it is a Helio P20 chip from MediaTek which gives life to the beast. This mid-range SoC, direct competitor to the Snapdragon 625, is accompanied by 3 GB of RAM. A configuration sufficient for the S41 to run Android without problems. The mobile is capable of managing several applications and juggling between them.

Proof of its serenity, the smartphone will only reach peaks at 35 ° C in the event of heavy loads.

Gamer-addicted adventurers may however be slightly disappointed. Unsurprisingly, the S41 is not really cut out for the game. Nevertheless, it proves capable of providing a rather good experience. If some concessions in terms of graphics are felt, the most demanding games run without real jolts.



The S41 offers a halftone headphone output. Nestled behind a waterproof protection, the 3.5 mm jack takes advantage of very low distortion and a good quality dynamic range. On the other hand, the problems start with a crosstalk still too high, and continue with a still very limited output power. If the smartphone wants to be all terrain, it will not survive a helmet even if it consumes a little energy.

For its part, the speaker, located on the lower edge of the terminal, displays a more than adequate output power. However, the sound tends to over saturate to be really pleasant to the ear, especially since the dynamic range is quite limited.


On its back, the Cat Phones S41 carries a simple module equipped with a 13 MP photo sensor. The application itself is rather classic. Disengageable, the exposure, the ISO, the focusing as well as the presence of HDR or not are adjustable quite easily. Various effects are also available.

In full hike or in full work, it would be nice to have on hand a smartphone with an irreproachable photo quality, in order to be able to immortalize the exotic places visited or the state of progress of the site. Unfortunately, most rugged smartphones don't rely on the photo. And the S41 is no exception.

On photos in bright light, the terminal does not do too badly, even if the image processing software smoothes the image a lot. The details suffer and the contrasts seem all the more forced as the final rendering is a little pale. The only small victory: on the outskirts, the terminal does not show any major shortcomings.

In low light, however, things deteriorate greatly. The noise invades the image quite spectacularly. The contrast drowns in the dark, the colors no longer stand out and a blur spoils the whole picture. If you want to take a photo of a landscape or site under the starry sky, be aware that you may need to explain what you wanted to capture.

Among rugged phones, the S41 therefore does slightly worse than the Trekker X3 which manages noise a little better in low light.

The front sensor of 8 MP presents for its part rather honest performances. The final result is rather pale and the focus is not adjustable, but the module has the advantage of not panicking excessively in case of backlight.

Finally, in video, the rear module is capable of shooting in 1080p and 30 fps. The image quality is good, but the light transitions are a little more chaotic this time.


Designed for adventurers, the S41 must have a solid battery. And as much to say that it does not disappoint. Its 5,000 mAh accumulator has it in its belly. Simulating standard use with sending text messages, standby, playing videos and music, our SmartViser protocol took 25 hours and 32 min to exhaust the machine. Solid performance. Concretely, this represents more than three days of autonomy.

Generous in effort, the S41 integrates the "Battery Share" application which allows it to discharge a little of its battery to another less autonomous smartphone.

It will however take a little more than 3 hours to fully charge the beast.


The S41 does its job of a rugged phone. Resistant to water, dust and even falls, it also offers a truly impressive autonomy. Only shortcomings, it is limited on a few aspects, such as night use which could have improved.