Original battery Green Cell for Dell Latitude Laptop E5440 E5540 high quality cells - branded Green Cell cells provide high real capacity, as well as durability (battery after 300 full charging (about 1 year of use) retains more than 80% capacity, and its durability is up to 1000 charging cycles, which is sufficient for about 2-3 years of unfailing operation) modern control electronics - thanks to it the battery works with the laptop exactly as the original battery, and the set of security features takes care of the computer and extends the life of the cells careful execution - the battery casing was made of the highest quality plastic and is perfectly tailored to the original pattern, so we can be sure that we will easily mount it on the laptop