Product advantages: 1. The inner lining is connected with sliding rails. When worn, it can ensure that the user's head remains at the center position of the safety helmet, thus enhancing the protective performance when the safety helmet receives the same impact force. 2. The "hook and groove" design of the cap shell and the inner lining's attachment makes the installation more stable. It is easy to disassemble and also helps to avoid the reduction of the safety helmet's protective performance due to improper carrying by the user. 3. Comfort des