(See Update below ...) It does not ensure the same operating time without recharging. Although higher capacity, faster charging, but with the same software and functions in operation, it takes approximately 4 hours (new) whereas the original battery took about 7 hours. Even after 2 years, it continued to assure me five hours without having to reconnect. Otherwise, easy assembly with a special screwdriver (see Velleman tri-wing) and intéresssant price. FYI, the end of life (almost 1000 cycles), the first battery seriously began to swell, preventing click functions of the trackpad, and had even made it out of the slot, twisting to pass the brackets (nothing serious, but better detect the problem quickly!) Update: battery received mid-May 2014, the end of July 2014, counted 74 cycles: the battery is discharged after 3 hours away (have to charge it 2-3 times a day or leave it plugged MBP - wifi, internet browsing software assets and 3-4) and the battery icon tells me 'Service battery' (maintenance / replacement battery required). Pretty bad ...