Cliff
This is a seat suspension system installed beneath the bicycle saddle.
Its structure includes front springs with a cross-shaped design,
a rear portion resembling a spring shock absorber,
and two rails at the bottom resembling those of a bicycle seat.
It is installed between the seatpost and the saddle.
Initially, it is treated as a saddle during installation,
and then it is fastened to this device using small screws.
The installation process is indeed quite simple. 
The actual riding experience is quite fascinating;
the suspension sensation is very noticeable.
Its sensitivity is even more responsive than the rear suspension of a mountain bike;
you can feel a slight movement with just a tiny shift in weight.
When I ride over bumpy surfaces, the sensation becomes more pronounced.
It effectively cushions the impact feel of potholes.
