... products have passed ISO9001. Duck Feather Badminton :Material: high grade duck feather,softwood ball headSpeed:75,76,77,78,79Weight:4.7- ... 5.2gDurability:100%Flight stability:AThe best quality of feather shuttlecock,durable,stable,exact speed,suitable for training and competition.Our ... forward to working with you in the near future. Duck Feather Badminton