What does the value of Class 2 medical devices refer to?

You can check the "Classification Catalog of Medical Devices" and the rules for classification of medical devices (Bureau Decree No. 15):

Article 5 The state implements classification and management of medical devices.

Class I refers to, medical devices whose safety and effectiveness are sufficiently ensured through routine management.

The second category refers to the safety and effectiveness of medical devices should be controlled.

The third category refers to the implantation of the human body; used to support, maintain life; potentially dangerous to the human body, its safety and effectiveness must be strictly controlled medical devices.

The specific categorization above is very clear.