War & Strike risks, which are normally excluded from the vessels' H&M insurance polices, are covered under a separate policy issued in accordance with the "Institute War & Strike Clauses (Clause 281)" terms and conditions. Certain risk areas are excluded under the W&S policies and W&S insurers are to be notified 48 hours before the ships' arrival at such excluded areas. Such call of the ships at excluded areas are subject Extra War Risk Insurance (EWRI) premium to be assessed by the respective W&S insurer. Unless otherwise agreed, EWRI premiums are valid for seven (7) days as of the ships' arrival at excluded area and any excess period would be subject to further EWRI premium.