The yonex aerosensa 10 feather shuttlecocks have been used in many world class events including the olympic games tournaments made from goose feathers and 100 solid portuguese cork these high quality shuttlecocks provide outstanding accuracy and flight they are also exceptionally durable which means that they require less frequent replacement than average shuttlecocks the yonex aerosensa 10 feather shuttlecocks are available in a pack of 25 dozen