DNV GL rules include requirements and additional class notations Ice(C) and Ice(E) for ships intended for service in waters with light ice conditions and localized drift ice, Ice(1C) through Ice(1A*) for vessels operating in northern Baltic Sea (corresponding to Finnish-Swedish ice classes 1C through 1A Super), an additional notation Ice(1A*F) for high-powered ships in regular traffic in heavy Baltic ice, and PC(1) through PC(7) for ships meeting the IACS Polar Class requirements. Ships engaged in icebreaking operations may be assigned an additional notation "Icebreaker" and ships designed to operate stern-first in ice an additional notation DAV.