A flashing for sealing around a pipe or conduit includes a dome portion with an opening with an inwardly extending lip, and a replaceable seal sized to fit in the dome opening so as to seal around a vent pipe. The seal includes a downwardly extending locking member to grip and lock the inwardly extending lip of the dome portion. The flashing may include a flange portion to facilitate installing the flashing on a roof. Once installed, the replaceable seal may be replaced without replacing the entire flashing, yet securely grips to the base of the flashing.