A floating rate note that pays periodical payment (coupons) calculated on the basis of the number of days during the preceding interest period in which a reference rate (3-month LIBOR, 6-month LIBOR) remains within a pre-defined corridor. If the reference rate lies within the corridor, the holder earn a much higher coupon than the holder of an identical plain-vanilla floating rate note (same issuer, maturity, reference rate, etc.). However, if the reference rate lies outside the corridor, no interest accrues to the holder.