1. Accurate cutting marks: top notch on the sternum, 
before the iliac spine can obviously touch, such as
easy to puncture.
2. Position: Feasible iliac spines centesis on
before training, and sternum punctures handle,
pierce through simulation marrow cavity has
obviously lost feeling, and can extract the
bone marrow.
3. Easy to replace the skin and simulated marrow cavity.
Note: The skin and all kinds of puncture cavities are replaceable.
