ZipString - As seen on Sharktank! ZipString is a captivating toy that defies gravity, floating a seemingly ordinary loop of string in mid-air. It masterfully balances the forces of gravity, lift, tension, and drag, creating an enchanting flight experience for the string. Every movement made by a Zipster (a ZipString user) is mirrored by the string, making it a truly interactive and magical playtime companion.