One of the main reason I went ahead with the CoolTec 4S is that it seems newer and not often on discount. Series 5 5140 is being sold at S$199 at most major electrical stores as well.
The other reason is that I do not need to use shaving foam with the CoolTec 4S as it will interfere with the Active Cooling Technology (ACT).
In order to experience the full Series 3 CoolTec effect, and benefit from Braun’s alcohol-based cleaning system that hygienically cleans 99.999% of germs, it is important that you do not use any shaving foams, gels or lotions which may act as a thermal insulator, and are not compatible with the alcohol-based cleaning solution (and may potentially also damage the device).
There are two models to the CoolTec CT 4. One is CoolTec CT 4S, and the other is CoolTec CT 4CC. 4S is a standalone unit while the 4CC comes with the Braun Automatic Clean&Charge (CC) Station  which makes it more expensive.
The two round metal contact points at the top are used to charge your shaver.
CoolTec 4S is made in Germany, 100% waterproof, and is designed to be safe to use in the showers. A full charge of 60 minutes will give you 45 minutes of shaving time. A quick charge of 5 minutes will provide you with just enough time for one shave.
There are three blades on the main shaver: two SensoBlades and one middle trimmer. Also, there is a slide out trimmer on the side of the shaver for mustache and sideburn shaping.
The main selling point of CoolTec is the ACT. At a touch of the ACT button (above the power button), the integrated thermo electro ceramic cooling element will turn electric power into a cool sensation when you shave. The ACT is located in between the two SensoBlades, just below the middle trimmer.
Braun recommends changing the main shaver blades every 18 months. And like most Brauns’ shavers, the CoolTec 4S is designed and tested to last at least seven years.
It would be nice if the cradle has more weight to it. I find it too light.
The ACT works as advertised without the need for shaving foam. It feels icy cold, and there is no irritation when I am shaving. You will get a close shave, almost as close as a regular razor shaver. The only downside is the whole process takes a little longer. At least from now on, you can save on shaving foam.