Give the feather a try! The YONEX Feather Shuttlecocks are precision-manufactured to ensure the correct speed, distance and stability performance. YONEX AEROSENSA shuttlecocks are all made of goose feathers and 100% solid cork. It’s the official shuttlecock for the world’s leading international tournaments. The precisely engineered technology in every lightweight YONEX feather shuttlecock is extensively checked and tested to guarantee consistent performance. The higher the grade (10 to 50), the more thorough the quality control.