EFB- und AGM- Technology for Start – Stop vehicles. The Duracell Extreme is built for use in environmentally friendly cars which incorporate the stop-start function. The EFB (Enhanced Flooded Battery) is used primarily in medium and small cars and LCV that have only basic stop-start features. The AGM (Absorbent Glass Mat) battery is mainly used on medium and executive/luxury vehicles, where more complex stop-start functions together with brake energy recuperation are standard. The Duracell Extreme premium products meet the demands of leading car manufacturers, and with a range of five types from 60Ah to 92Ah are the first choice for fuel efficient cars.