Feature: Uses copyrighted chain spring with super bounce back and durable.

特点：采用专利精钢门环弹簧，超强回弹力，坚固耐力。

youdao

Feature: Uses copyrighted chain spring with super bounce back and durable.

特点：采用专利精钢门环弹簧，超强回弹力，坚固耐力。

youdao