This design was only seen after years of silence. The original design mainly considered the differences in the market.
This is different. This is the first one. The second is that this design has two functions: one is ventilation, and the other is that there will be no space when the arm is lifted. This is suitable for cold weather, and there is no room for wearing one or more outside. The second is to reduce the connectivity of body-shaping thermal underwear even when wearing too many clothes, making it easier for the arm to lift and facilitate the arm movement, which is suitable for both north and south places.
For example, it is warmer in the south than in the north in winter. Generally, it is enough to wear a coat to keep people warm and adjust their body temperature slightly. Generally speaking, it is more convenient than not having an opening!