All Arc 5 variations from the second generation and up feature this smaller shaving head.
The third Arc 5 generation also introduced some impressive flexing capabilities of the shaving unit (revision C and up).
However, I wouldn’t consider that a must-have feature when trying to decide between a second or third-generation Arc 5 for example.
而刀片只係多左金色果條foil,等剃果時無咁易受傷,而內刀頭二三代甚至一樣,
the biggest change brought by the third Arc 5 generation is a new outer foil.
It now features two so-called comfort rollers (the gold bars in the image below) that allow the shaving head to glider easier on the skin and prevent the user from applying excessive pressure (which can cause razor burn).
And this update to the foil does work and I will discuss it later on when I’ll compare the performance of the various Arc 5 models.
Interestingly, while the outer foil is new, the two removable inner blades (part number WES9170) are the same ones used by the older shavers in generations 1 and 2.