Krone Navy Filters - Mistral class helicopter carriers - Krone special Fuel Filters - more than 30 Krone Series casted KSF filters EN-GJS-400 LT with 3.2 BV certification were delivered for new helicopter refueling stations and other fuel systems on the Mistral class carriers which is an Amphibious Assault & Command ship series - the most modern and sophisticated helicopter carrier series manufactured in France.