Ful Cinch Sack Ful Drawstring Cinch Sack Air-bv1 This is a drawstring sackpack from FUL. This is a versatile bag that can be worn over one or both shoulders using the drawstrings to provide tension. It is is perfect for trips to gym, sporting events, school and many other activities. Made of tough Material this is another sleek, durable product from FUL.