The Strapper has 3 purposes:
1) Keeps straps from being seen when wearing any kind of sleeveless Tops/ Dresses even Racerbacks!
2) Keeps straps in place! No more falling off ones shoulders
Woman love them for their Bating Suits for this reason
3) Lifts and Supports! Woman also love to use the Strapper for working out instead of Racerback Bras for the extra support it gives!