Balance transfer cards offer 0% APR for a promotional period (typically 12–21 months). Transferring high-rate credit card debt to one of these cards eliminates interest during the promo period, letting your payments go entirely to principal.
Key risks: transfer fees (usually 3–5% of transferred amount), and deferred interest on any remaining balance when the promo period ends. Only use balance transfers with a realistic plan to pay off the balance before the intro period expires.