In Notional V2, an fCash token's denomination currency is distinct from it's settlement currency. fCash is denominated in an underlying token like DAI or USDC, but it is settled in a cToken like cDAI or cUSDC. For example, upon maturity, 100 Dec 1 2021 fDAI is not directly redeemable for 100 DAI, rather it is redeemable for 100 DAI's worth of cDAI which is then freely convertible into DAI at the user's will.