Comparison Philips Series 9000 S9711/31 vs Philips SensoTouch 3D RQ1275

Models feature waterproof casing with varying levels of protection, often indicated by two numbers. The first number pertains to dust resistance and is often marked as X. The second number reflects moisture resistance, particularly water. For instance, IPX3 and IPX4 offer splash protection, IPX5 and IPX6 enable shower use, while electric shavers with IPX7 can be submerged underwater for up to 30 minutes.

— Built-in trimmer. Device for trimming the contours of facial hair. A trimmer is similar to a clipper, but smaller and better suited for fine work. Located directly on the body of the device.

— Blade for hair cutting. Removable version of the trimmer (read more about the trimmer above), made in the form of a replaceable nozzle and is installed instead of the main nozzle with shaving heads. Thanks to this, the trimmer can be made wider than the built-in trimmer, and overall more efficient.

— Nozzle for ears and nose. The cylindrical nozzle of small diameter allows you to penetrate the inlet and ear and remove unwanted vegetation from there. It is installed mainly on top of the main nozzle.

— Universal comb. Such a nozzle can be useful for regular care of the stubble or beard, when you need to trim, shorten, and not just shave. Length adjustment allows you to select the desired value for a particular area or depending on the image and type of "hairstyle".

Model of replacement head(s) compatible with electric shaver. This data will be useful primarily when looking for spare nozzles.

— Turbo mode. The function of a short-term increase in the speed of rotation of the motor. This increases the performance of the shaver, which can be especially important when working with thick hair or in hard-to-reach areas. Note that the turbo mode, usually, is not intended for long-term operation.

— Auto-detection of bristles. The electric shaver's head contains a sensor to detect bristle density or stiffness. Through the automatic stubble feature, the shaver's motor adjusts power according to the skin area's requirements. This capability facilitates effective one-pass shaving, even with thick stubble. As the shaving head transitions from dense to moderate bristles, the motor power decreases automatically. This not only conserves battery life but also provides a gentler experience for the skin.

— Floating head/foil. The floating or movable shaving head(s) are capable of moving relative to the shaving unit and shaver body. Such a system follows the contours of the face during shaving, which ensures a tighter fit of the shaving heads to the skin, as a result — a cleaner and better shave, especially in difficult areas.

— Possibility of washing with water. Possibility of washing the shaving unit with water. This method is often much more convenient and effective than dry cleaning with a brush or...other method. Note that being washable with water does not necessarily mean wet shaving (see above).

— Cleaning indicator. A special indicator that notifies the user of the need to clean the shaver.

— Self-sharpening blades. Blades made using a special technology, thanks to which they sharpen themselves, due to friction against each other in the process. Thus, the blades remain sharp at all times, and their maintenance is limited to the replacement of worn blades.

— Child lock. Shavers featuring a safety switch are designed to activate only when held in the user's hand and intentionally turned on. This design prevents unintended activations, such as during travel when the device might shake inside luggage, avoiding unnecessary battery drain during idle moments.

— Case. Cases include all kinds of rigid structures for storing a shaver. Cases in the form of handbags made of thick fabric also fall into this category. In addition to reliable storage of the device, they also elevate the model to the highest class. In more low-cost electric shavers, a much more primitive fabric case is included in the package.

— Charging stand. A special stand on which the shaver can be installed to charge the batteries. There are no fundamental technical differences between such charging and charging from a power cord, the main difference is that the stand can also be used to store a shaver. Therefore, shavers with a charging stand are well suited for home use.

— Wireless charging. A special stand that charges the shaver without a precise connection through the plug — just put the electric shaver on it and the battery pack will automatically start recharging. This saves the user the hassle of connecting wires and reduces wear on the connectors. On the other hand, such a function has a significant impact on the cost of the battle and increases the duration of the charging process itself, since the charging platforms themselves are made low-power for safety reasons.

— Self-cleaning station. It is a special stand where the shaver is installed for automatic maintenance. This maintena...nce, as the name suggests, primarily includes cleaning — the shaving unit is cleaned of hairs and dust - as well as charging the battery. In addition, self-cleaning systems can provide lubrication and disinfection of the shaving unit, but this function is less common and requires the use of consumables (oil and disinfectant).

— Facial brush. It is convenient to clean the face from the cut bristles with a brush. The brush that comes with an electric shaver usually has a medium bristle length. Some electric shavers are equipped with a universal brush, which is designed for both cleaning the face and combing the beard and mustache.

— Li-Ion. Currently, the prevailing battery type is Lithium-ion (Li-Ion), known for its high energy density, compact size, and light weight. Li-Ion batteries offer approximately 400 charge-discharge cycles on average. These batteries exhibit minimal self-discharge and lack a significant "memory effect" (capacity reduction due to charging a partially drained battery). However, they are sensitive to cold temperatures and require high-quality charging currents.

— Li-pol. Lithium-polymer (Li-Pol) batteries maintain stable output voltage even during significant discharge. These batteries offer an average lifespan of about 800 charge-discharge cycles. Unlike some battery types, Li-Pol batteries don't exhibit a memory effect, and they operate reliably within a wide temperature range of -20 to +40°C. However, they are sensitive to deep discharge and overcharging. To address this, specialized chargers employing suitable power supply algorithms for the lithium polymer context are recommended for maintenance.

— Ni-Mh. Nickel-metal hydride (Ni-MH) batteries excel in managing substantial charge and discharge currents, making them suitable for power-demanding electric motors and rapid charging. These batteries now boast impressive longevity, enduring around 1000 to 1500 charge-discharge cycles, while maintaining an eco-friendly nature. In comparison to Li-Ion, Ni-MH batteries appear bulkier and add weight to the device, yet they offer a more economical option.

The presence in the design of the electric shaver charge level indicator.

It's important to highlight that in this context, an indicator refers specifically to a visual representation of the charge level. This could manifest as a battery icon or a percentage displayed on the display. Such an indicator significantly simplifies battery monitoring, minimizing the possibility of being unexpectedly left with a depleted battery.

The ability to switch the voltage for which the shaver is designed, adjusting it to the characteristics of various electrical networks. This feature is useful for those who often travel abroad: in different countries, the voltage in the outlet can also be different. For example, in Europe and most Asian countries, 230 V networks are used, but in North America the voltage is 110 V.

In the simplest models with this function, the voltage is switched manually, more advanced shavers have an automatic network adjustment system.

The presence on the body of the shaver own display, which can display various service information. The display can be equipped with its own backlight. Its presence makes the use of the shaver more convenient, but significantly affects the price of the device.