It can be regarded as a guided active protective net. It is mainly used to guide the broken rock stratum on the slope to the protection system at the lower part of the slope. the middle and lower active protective net system is different from the traditional active protective net system. There is a certain gap between the net and the slope surface, which is used to guide the rockfall to the lower rockfall collection area, and at the same time, prevent the rockfall from splashing and bouncing to endanger the safety of people and property in the protected area. It effectively avoids many disadvantages of traditional active and passive interception systems that are inconvenient to clean and easy to cause secondary harm. According to different requirements, common opening curtain nets have different models. The higher the number, the higher the energy level they can withstand.