Traduciendo paso 3
The lower case is secured by ten Phillips #00 screws. There are no pentalobe screws since Apple still considers the RAM and hard drive to be user-replaceable. However, like the machine this replaces, the battery is not user-replaceable (at least according to Apple).
The RAM in this machine is PC3-10600 RAM. That's the same RAM used in the 2010 revision of the 21.5" and 27" iMacs, but different from earlier Apple laptops. PC3-10600 RAM is backwards compatible with the PC3-8500 RAM in older MacBook Pro Unibody machines, but you can't use older PC3-8500 RAM in this machine.