Y's by Yohji Yamamoto Women's Apparel Size Chart The day will flow easier with a touch of style carrying the Y's by Yohji Yamamoto™ Knap Sack. Backpack made of polyester and nylon. Top carrying handle. Drawstring tie closure. Dual shoulder straps. Two exterior slip pockets. Polka dot pattern throughout. Flat base. Lined interior features a zipper pocket and two slip pockets. Made in Japan. This item may ship with an attached security tag. Merchandise returned without the original security tag attached or a damaged tag may not qualify for a refund.