On the one hand they differ in the display, S9711 has a digital display, S9111 has bars. They also have different shaving settings, the S9711 has 3 speed settings, Slow, Medium and Fast, where Slow is for a more skin-friendly result. S9111 has only one speed, Medium. Many customers have problems with skin irritation in the neck area and use the slow mode there, the cheek area is not a problem and goes faster with more speed.

The S9711/31 has a battery indicator display, the S9111/31 has only one bar. In addition, the S9711/31 has 3 shaving settings for fast, medium and slow shaving, the S9111/31 only has 1. And last but not least, the battery life of the S9711/31 is 60 minutes and the S9111/31 only 50 minutes.